🚨 CVE-2026-93783
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame
rfcomm_recv_frame() casts skb->data to struct rfcomm_hdr and dereferences
hdr->addr and hdr->ctrl without validating skb->len first. A truncated
frame with skb->len less than the minimum header size causes an
out-of-bounds read of uninitialized memory. Additionally, a zero-length
frame causes skb->len-- to underflow to UINT_MAX, making
skb_tail_pointer() read far past the buffer.
Commit 23882b828c3c ("Bluetooth: RFCOMM: validate skb length in MCC
handlers") fixed the same class of missing-length-check bugs in the MCC
sub-handlers, but the top-level rfcomm_recv_frame() was left unfixed.
KMSAN reports:
BUG: KMSAN: uninit-value in rfcomm_run
...
Uninit was created at:
__alloc_skb+0x474/0xb60
vhci_write+0xe9/0x870
Fix this by rejecting frames smaller than sizeof(struct rfcomm_hdr) + 1
(the minimum frame must have a 3-byte header and a 1-byte FCS).
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame
rfcomm_recv_frame() casts skb->data to struct rfcomm_hdr and dereferences
hdr->addr and hdr->ctrl without validating skb->len first. A truncated
frame with skb->len less than the minimum header size causes an
out-of-bounds read of uninitialized memory. Additionally, a zero-length
frame causes skb->len-- to underflow to UINT_MAX, making
skb_tail_pointer() read far past the buffer.
Commit 23882b828c3c ("Bluetooth: RFCOMM: validate skb length in MCC
handlers") fixed the same class of missing-length-check bugs in the MCC
sub-handlers, but the top-level rfcomm_recv_frame() was left unfixed.
KMSAN reports:
BUG: KMSAN: uninit-value in rfcomm_run
...
Uninit was created at:
__alloc_skb+0x474/0xb60
vhci_write+0xe9/0x870
Fix this by rejecting frames smaller than sizeof(struct rfcomm_hdr) + 1
(the minimum frame must have a 3-byte header and a 1-byte FCS).
🎖@cveNotify
🚨 CVE-2026-93784
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie()
The KASAN allocation trace shows that a malformed IE buffer is
stored via SIOCSIWGENIE (cfg80211_wext_siwgenie()) without any
validation. The crash trace shows that a subsequent SIOCSIWESSID
triggers a connection attempt which calls cfg80211_sme_get_conn_ies()
to process the stored IE buffer, causing:
- An out-of-bounds read in skip_ie() which reads ies[pos+1]
(the length byte) past the end of the 1-byte buffer.
- An integer underflow in the memcpy size argument when offs
returned by ieee80211_ie_split() exceeds ies_len, causing
unsigned subtraction to wrap to SIZE_MAX and triggering a
fortify panic.
Fix this by validating the IE buffer in cfg80211_wext_siwgenie()
before storing it.
[drop unnecessary ie_len check, update commit message]
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie()
The KASAN allocation trace shows that a malformed IE buffer is
stored via SIOCSIWGENIE (cfg80211_wext_siwgenie()) without any
validation. The crash trace shows that a subsequent SIOCSIWESSID
triggers a connection attempt which calls cfg80211_sme_get_conn_ies()
to process the stored IE buffer, causing:
- An out-of-bounds read in skip_ie() which reads ies[pos+1]
(the length byte) past the end of the 1-byte buffer.
- An integer underflow in the memcpy size argument when offs
returned by ieee80211_ie_split() exceeds ies_len, causing
unsigned subtraction to wrap to SIZE_MAX and triggering a
fortify panic.
Fix this by validating the IE buffer in cfg80211_wext_siwgenie()
before storing it.
[drop unnecessary ie_len check, update commit message]
🎖@cveNotify
🚨 CVE-2026-93785
In the Linux kernel, the following vulnerability has been resolved:
cifs: validate idmap key payload length
The cifs.idmap key type stores its payload length in key->datalen, which
is limited to U16_MAX. Accepting a larger key payload truncates the
recorded length and can make later users interpret the payload using
inconsistent bounds.
Reject oversized preparsed payloads before allocating or copying them.
This keeps key->datalen consistent with the stored data for both inline
and separately allocated idmap payloads.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
cifs: validate idmap key payload length
The cifs.idmap key type stores its payload length in key->datalen, which
is limited to U16_MAX. Accepting a larger key payload truncates the
recorded length and can make later users interpret the payload using
inconsistent bounds.
Reject oversized preparsed payloads before allocating or copying them.
This keeps key->datalen consistent with the stored data for both inline
and separately allocated idmap payloads.
🎖@cveNotify
🚨 CVE-2026-93786
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: preserve VFS inherited POSIX ACL mask
The VFS initializes a child's POSIX ACL from the parent's default ACL and
the requested creation mode. Do not mutate the parent ACL or overwrite the
child's VFS-computed access and default ACLs afterwards.
This preserves restrictive ACL_MASK entries and prevents SMB object creation
from widening effective permissions.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: preserve VFS inherited POSIX ACL mask
The VFS initializes a child's POSIX ACL from the parent's default ACL and
the requested creation mode. Do not mutate the parent ACL or overwrite the
child's VFS-computed access and default ACLs afterwards.
This preserves restrictive ACL_MASK entries and prevents SMB object creation
from widening effective permissions.
🎖@cveNotify
🚨 CVE-2026-93787
In the Linux kernel, the following vulnerability has been resolved:
smb: client: bound dirent name against end of SMB response in cifs_filldir
cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST /
FIND_NEXT response using a length (de.namelen) supplied by the server.
The kmalloc'd SMB response buffer is bounded, but nothing checks that
de.name + de.namelen still lies inside that buffer before the eventual
filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes.
A hostile SMB1 server that returns an oversized FileNameLength in a
directory entry therefore causes memchr() to read past the end of the
response slab buffer. Reachable from any user who can list a directory
on a CIFS mount served by an attacker-controlled server (getdents64()
on the mounted directory):
BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80
Read of size 1 at addr ffff88800e0640cc by task poc/115
Call Trace:
dump_stack_lvl+0x64/0x80
print_report+0xce/0x620
kasan_report+0xec/0x120
memchr+0x71/0x80
filldir64+0x4c/0x6a0
cifs_filldir.constprop.0+0x9bb/0x1e00
cifs_readdir+0x2101/0x3380
iterate_dir+0x19c/0x520
__x64_sys_getdents64+0x126/0x210
do_syscall_64+0x107/0x5a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Pass the end-of-response pointer down to cifs_filldir() and reject
entries whose name would extend past that boundary.
This bug was discovered by Artiphishell's vTriage pipeline, which
generated a userspace reproducer (an emulated hostile SMB1 server plus
a getdents64() client) that reliably triggers the KASAN report on an
unpatched kernel. The fix below was drafted with the Claude coding
assistant; a userspace reproducer is available on request.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
smb: client: bound dirent name against end of SMB response in cifs_filldir
cifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST /
FIND_NEXT response using a length (de.namelen) supplied by the server.
The kmalloc'd SMB response buffer is bounded, but nothing checks that
de.name + de.namelen still lies inside that buffer before the eventual
filldir64() -> verify_dirent_name() -> memchr() reads namelen bytes.
A hostile SMB1 server that returns an oversized FileNameLength in a
directory entry therefore causes memchr() to read past the end of the
response slab buffer. Reachable from any user who can list a directory
on a CIFS mount served by an attacker-controlled server (getdents64()
on the mounted directory):
BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80
Read of size 1 at addr ffff88800e0640cc by task poc/115
Call Trace:
dump_stack_lvl+0x64/0x80
print_report+0xce/0x620
kasan_report+0xec/0x120
memchr+0x71/0x80
filldir64+0x4c/0x6a0
cifs_filldir.constprop.0+0x9bb/0x1e00
cifs_readdir+0x2101/0x3380
iterate_dir+0x19c/0x520
__x64_sys_getdents64+0x126/0x210
do_syscall_64+0x107/0x5a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Pass the end-of-response pointer down to cifs_filldir() and reject
entries whose name would extend past that boundary.
This bug was discovered by Artiphishell's vTriage pipeline, which
generated a userspace reproducer (an emulated hostile SMB1 server plus
a getdents64() client) that reliably triggers the KASAN report on an
unpatched kernel. The fix below was drafted with the Claude coding
assistant; a userspace reproducer is available on request.
🎖@cveNotify
🚨 CVE-2026-93788
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: acpi: validate WGDS table revision index
Check tbl_rev bounds before BIT(tbl_rev) to avoid undefined shifts when
firmware reports an invalid revision value.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: acpi: validate WGDS table revision index
Check tbl_rev bounds before BIT(tbl_rev) to avoid undefined shifts when
firmware reports an invalid revision value.
🎖@cveNotify
🚨 CVE-2026-93789
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: bound aligned TLV advance in FW parser
Validate ALIGN(tlv_len, 4) against remaining parser length before
consuming bytes from the firmware image.
This avoids length underflow on malformed TLVs.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: bound aligned TLV advance in FW parser
Validate ALIGN(tlv_len, 4) against remaining parser length before
consuming bytes from the firmware image.
This avoids length underflow on malformed TLVs.
🎖@cveNotify
🚨 CVE-2026-93790
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif
mvmsta->tid_data was indexed by the TFD loop counter 'i' instead of
the actual TID value 'tid'. This writes lq_color into a random tid_data
slot unrelated to the BA entry.
Since multi-TID blockack is not really in use, 'i' was always 0 and no
harm was done.
Add a out-of-bound check before accessing the array.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif
mvmsta->tid_data was indexed by the TFD loop counter 'i' instead of
the actual TID value 'tid'. This writes lq_color into a random tid_data
slot unrelated to the BA entry.
Since multi-TID blockack is not really in use, 'i' was always 0 and no
harm was done.
Add a out-of-bound check before accessing the array.
🎖@cveNotify
🚨 CVE-2026-93791
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: add a check on the tid coming from the firmware
ba_notif->tid is a firmware-controlled u8 that is used directly
as an array index into tid_data[] without any validation. Add a
bounds check against IWL_MAX_TID_COUNT before dereferencing the
array.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: add a check on the tid coming from the firmware
ba_notif->tid is a firmware-controlled u8 that is used directly
as an array index into tid_data[] without any validation. Add a
bounds check against IWL_MAX_TID_COUNT before dereferencing the
array.
🎖@cveNotify
🚨 CVE-2026-93792
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix a possible underflow
We shouldn't trust the firmware about the length of the wowlan packet.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix a possible underflow
We shouldn't trust the firmware about the length of the wowlan packet.
🎖@cveNotify
🚨 CVE-2026-93793
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: validate TX_CMD response layout
TX_CMD parsing uses frame_count to walk status entries and then
read the trailing SCD SSN. Make the minimum-length check follow
that exact runtime layout calculation before parsing the payload.
For new TX API, reject TX_CMD responses with frame_count != 1 and
warn/return in the aggregation handler to document that aggregated
accounting is expected via BA notifications.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: validate TX_CMD response layout
TX_CMD parsing uses frame_count to walk status entries and then
read the trailing SCD SSN. Make the minimum-length check follow
that exact runtime layout calculation before parsing the payload.
For new TX API, reject TX_CMD responses with frame_count != 1 and
warn/return in the aggregation handler to document that aggregated
accounting is expected via BA notifications.
🎖@cveNotify
🚨 CVE-2026-93794
In the Linux kernel, the following vulnerability has been resolved:
smb/client: flush dirty data before punching a hole
Punching a hole after a large buffered write may leave the range
reported as data. Reproduce it with:
xfs_io -f \
-c "pwrite -b 3m -S 0x61 0 3m" \
-c "fpunch 1m 1m" \
-c "seek -h 0" \
-c "seek -d 1m" \
/mnt/test/repro
Punching 1 MiB at offset 1 MiB should produce:
0 1 MiB 2 MiB 3 MiB
| DATA | HOLE | DATA | EOF
Instead, the entire file is reported as data. SEEK_HOLE(0) returns EOF,
and SEEK_DATA(1M) returns 1M.
This happens because a dirty folio spanning the punched range can be
written back after the punch and refill the hole.
Fix this by flushing and waiting for dirty data in the punched range
before invalidating the page cache and issuing FSCTL_SET_ZERO_DATA.
The xfstests generic/539 pass against Samba/ksmbd with this change.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
smb/client: flush dirty data before punching a hole
Punching a hole after a large buffered write may leave the range
reported as data. Reproduce it with:
xfs_io -f \
-c "pwrite -b 3m -S 0x61 0 3m" \
-c "fpunch 1m 1m" \
-c "seek -h 0" \
-c "seek -d 1m" \
/mnt/test/repro
Punching 1 MiB at offset 1 MiB should produce:
0 1 MiB 2 MiB 3 MiB
| DATA | HOLE | DATA | EOF
Instead, the entire file is reported as data. SEEK_HOLE(0) returns EOF,
and SEEK_DATA(1M) returns 1M.
This happens because a dirty folio spanning the punched range can be
written back after the punch and refill the hole.
Fix this by flushing and waiting for dirty data in the punched range
before invalidating the page cache and issuing FSCTL_SET_ZERO_DATA.
The xfstests generic/539 pass against Samba/ksmbd with this change.
🎖@cveNotify
🚨 CVE-2026-93796
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: pcie: null RX pointers after free
When iwl_pcie_tx_init() fails after RX init, nic init unwinds via
iwl_pcie_rx_free().
The freed RX members stayed non-NULL on the live transport object,
so later teardown or retry could touch stale RX state.
Set rx_pool, global_table, rxq, and alloc_page to NULL after free
to make repeated cleanup and retry paths safe.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: pcie: null RX pointers after free
When iwl_pcie_tx_init() fails after RX init, nic init unwinds via
iwl_pcie_rx_free().
The freed RX members stayed non-NULL on the live transport object,
so later teardown or retry could touch stale RX state.
Set rx_pool, global_table, rxq, and alloc_page to NULL after free
to make repeated cleanup and retry paths safe.
🎖@cveNotify
🚨 CVE-2026-93797
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix an off-by-1 boundary check
Before looking at the 11th byte, check the length is big enough.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: fix an off-by-1 boundary check
Before looking at the 11th byte, check the length is big enough.
🎖@cveNotify
🚨 CVE-2026-93798
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix reloc root cleanup in merge_reloc_roots()
If the root we got has zero root refs in its root item, we are resetting
the root's ->reloc_root without using barriers like we do everywhere else.
Sashiko complained about this while reviewing another patch, and it's
correct (see the Link tag below).
Also, we should not clear BTRFS_ROOT_DEAD_RELOC_TREE from the root unless
the root points to the reloc root we have.
Fix this by using clear_reloc_root(), which issues the memory barrier
after setting the root's ->reloc_root to NULL and before clearing the bit
BTRFS_ROOT_DEAD_RELOC_TREE from the root.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix reloc root cleanup in merge_reloc_roots()
If the root we got has zero root refs in its root item, we are resetting
the root's ->reloc_root without using barriers like we do everywhere else.
Sashiko complained about this while reviewing another patch, and it's
correct (see the Link tag below).
Also, we should not clear BTRFS_ROOT_DEAD_RELOC_TREE from the root unless
the root points to the reloc root we have.
Fix this by using clear_reloc_root(), which issues the memory barrier
after setting the root's ->reloc_root to NULL and before clearing the bit
BTRFS_ROOT_DEAD_RELOC_TREE from the root.
🎖@cveNotify
🚨 CVE-2026-93799
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: validate sta_id in BA window status notif
BA_WINDOW_STATUS_NOTIFICATION_ID extracts a 5-bit sta_id from the
firmware notification and uses it to index fw_id_to_mac_id[] without
bounds checking. Validate sta_id before array access to prevent
out-of-bounds indexing.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: validate sta_id in BA window status notif
BA_WINDOW_STATUS_NOTIFICATION_ID extracts a 5-bit sta_id from the
firmware notification and uses it to index fw_id_to_mac_id[] without
bounds checking. Validate sta_id before array access to prevent
out-of-bounds indexing.
🎖@cveNotify
🚨 CVE-2026-93800
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix use-after-free on reloc root after error in insert_dirty_subvol()
If during relocation we fail in insert_dirty_subvol() because
btrfs_update_reloc_root() returned an error, we will leave a root's
reloc_root field pointing to a reloc root that was freed instead of NULL,
resulting later in a use-after-free, or double free attempt during
unmount.
The sequence of steps is this:
1) During relocation the call to btrfs_update_reloc_root() in
insert_dirty_subvol() fails, so insert_dirty_subvol() returns the
error to merge_reloc_root() without adding the root to the list
rc->dirty_subvol_roots;
2) Then merge_reloc_root() aborts the current transaction because
insert_dirty_subvol() returned an error;
3) Up the call chain, merge_reloc_roots() gets the error, adds the
reloc root for root X to the local reloc_roots list and jumps to the
'out' label, where it calls free_reloc_roots() to free all the reloc
roots in the local reloc_roots list. This frees the reloc root for
root X;
4) We go up the call chain to relocate_block_group() which calls
clean_dirty_subvols() to go over dirty roots and set their
->reloc_root field to NULL, but root X is not in the dirty_subvol_roots
list, so its ->reloc_root still points to a reloc root;
5) Relocation finishes, with an error and a transaction abort, but the
->reloc_root field for root X still points to the reloc root that was
freed in step 3;
6) When unmounting the fs we end up calling:
btrfs_free_fs_roots()
btrfs_drop_and_free_fs_root()
--> calls btrfs_put_root() against root X's ->reloc_root
which is not NULL and points to the already freed
reloc root in step 4 above
Resulting in a use-after-free to a double free attempt.
Syzbot reported this with the following dmesg/syslog:
[ 106.004389][ T5339] BTRFS error (device loop0 state A): Transaction aborted (error -5)
[ 106.014266][ T5339] BTRFS: error (device loop0 state A) in merge_reloc_root:1655: errno=-5 IO failure
[ 106.021891][ T1061] BTRFS error (device loop0 state A): error while writing out transaction: -5
[ 106.026964][ T1061] BTRFS warning (device loop0 state A): Skipping commit of aborted transaction.
[ 106.033807][ T5340] BTRFS error (device loop0 state A): bdev /dev/loop0 errs: wr 3, rd 0, flush 0, corrupt 0, gen 0
[ 106.039265][ T1061] BTRFS: error (device loop0 state A) in cleanup_transaction:2067: errno=-5 IO failure
[ 106.044382][ T5339] BTRFS info (device loop0 state EA): forced readonly
[ 106.074329][ T5339] BTRFS: error (device loop0 state EA) in merge_reloc_roots:1887: errno=-5 IO failure
[ 106.081004][ T5356] BTRFS info (device loop0 state EA): scrub: started on devid 1
[ 106.085611][ T5339] BTRFS info (device loop0 state EA): balance: ended with status: -30
[ 106.089517][ T5356] BTRFS info (device loop0 state EA): scrub: not finished on devid 1 with status: -30
[ 106.662365][ T5338] BTRFS info (device loop0 state EA): last unmount of filesystem 3a375e4e-b156-4d76-a2ad-16e198ce1409
[ 106.682946][ T5338] ==================================================================
[ 106.686574][ T5338] BUG: KASAN: slab-use-after-free in btrfs_put_root+0x2f/0x250
[ 106.690090][ T5338] Write of size 4 at addr ffff88803f978630 by task syz.0.0/5338
[ 106.693173][ T5338]
[ 106.694279][ T5338] CPU: 0 UID: 0 PID: 5338 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
[ 106.694293][ T5338] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 106.694300][ T5338] Call Trace:
[ 106.694308][ T5338] <TASK>
[ 106.694314][ T5338] dump_stack_lvl+0xe8/0x150
[ 106.694331][ T5338] print_address_description+0x55/0x1e0
[ 106.694343][ T5338] ? btrfs_put_root+0x2f/0x250
[ 106.694358][ T5338] print_report+0x58/0x70
[ 106.
---truncated---
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix use-after-free on reloc root after error in insert_dirty_subvol()
If during relocation we fail in insert_dirty_subvol() because
btrfs_update_reloc_root() returned an error, we will leave a root's
reloc_root field pointing to a reloc root that was freed instead of NULL,
resulting later in a use-after-free, or double free attempt during
unmount.
The sequence of steps is this:
1) During relocation the call to btrfs_update_reloc_root() in
insert_dirty_subvol() fails, so insert_dirty_subvol() returns the
error to merge_reloc_root() without adding the root to the list
rc->dirty_subvol_roots;
2) Then merge_reloc_root() aborts the current transaction because
insert_dirty_subvol() returned an error;
3) Up the call chain, merge_reloc_roots() gets the error, adds the
reloc root for root X to the local reloc_roots list and jumps to the
'out' label, where it calls free_reloc_roots() to free all the reloc
roots in the local reloc_roots list. This frees the reloc root for
root X;
4) We go up the call chain to relocate_block_group() which calls
clean_dirty_subvols() to go over dirty roots and set their
->reloc_root field to NULL, but root X is not in the dirty_subvol_roots
list, so its ->reloc_root still points to a reloc root;
5) Relocation finishes, with an error and a transaction abort, but the
->reloc_root field for root X still points to the reloc root that was
freed in step 3;
6) When unmounting the fs we end up calling:
btrfs_free_fs_roots()
btrfs_drop_and_free_fs_root()
--> calls btrfs_put_root() against root X's ->reloc_root
which is not NULL and points to the already freed
reloc root in step 4 above
Resulting in a use-after-free to a double free attempt.
Syzbot reported this with the following dmesg/syslog:
[ 106.004389][ T5339] BTRFS error (device loop0 state A): Transaction aborted (error -5)
[ 106.014266][ T5339] BTRFS: error (device loop0 state A) in merge_reloc_root:1655: errno=-5 IO failure
[ 106.021891][ T1061] BTRFS error (device loop0 state A): error while writing out transaction: -5
[ 106.026964][ T1061] BTRFS warning (device loop0 state A): Skipping commit of aborted transaction.
[ 106.033807][ T5340] BTRFS error (device loop0 state A): bdev /dev/loop0 errs: wr 3, rd 0, flush 0, corrupt 0, gen 0
[ 106.039265][ T1061] BTRFS: error (device loop0 state A) in cleanup_transaction:2067: errno=-5 IO failure
[ 106.044382][ T5339] BTRFS info (device loop0 state EA): forced readonly
[ 106.074329][ T5339] BTRFS: error (device loop0 state EA) in merge_reloc_roots:1887: errno=-5 IO failure
[ 106.081004][ T5356] BTRFS info (device loop0 state EA): scrub: started on devid 1
[ 106.085611][ T5339] BTRFS info (device loop0 state EA): balance: ended with status: -30
[ 106.089517][ T5356] BTRFS info (device loop0 state EA): scrub: not finished on devid 1 with status: -30
[ 106.662365][ T5338] BTRFS info (device loop0 state EA): last unmount of filesystem 3a375e4e-b156-4d76-a2ad-16e198ce1409
[ 106.682946][ T5338] ==================================================================
[ 106.686574][ T5338] BUG: KASAN: slab-use-after-free in btrfs_put_root+0x2f/0x250
[ 106.690090][ T5338] Write of size 4 at addr ffff88803f978630 by task syz.0.0/5338
[ 106.693173][ T5338]
[ 106.694279][ T5338] CPU: 0 UID: 0 PID: 5338 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
[ 106.694293][ T5338] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 106.694300][ T5338] Call Trace:
[ 106.694308][ T5338] <TASK>
[ 106.694314][ T5338] dump_stack_lvl+0xe8/0x150
[ 106.694331][ T5338] print_address_description+0x55/0x1e0
[ 106.694343][ T5338] ? btrfs_put_root+0x2f/0x250
[ 106.694358][ T5338] print_report+0x58/0x70
[ 106.
---truncated---
🎖@cveNotify
🚨 CVE-2026-93801
In the Linux kernel, the following vulnerability has been resolved:
smb/client: zero-initialize stack-allocated cifs_open_info_data
Stack-allocated cifs_open_info_data may contain random data.
This can make some fields have wrong value if they are not set later.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
smb/client: zero-initialize stack-allocated cifs_open_info_data
Stack-allocated cifs_open_info_data may contain random data.
This can make some fields have wrong value if they are not set later.
🎖@cveNotify
🚨 CVE-2026-93802
In the Linux kernel, the following vulnerability has been resolved:
wifi: rsi: validate beacon length before fixed buffer copy
rsi_prepare_beacon() copies the mac80211 beacon frame after
FRAME_DESC_SZ into a management skb whose usable tailroom may be smaller
than MAX_MGMT_PKT_SIZE after alignment.
Validate the beacon length against the actual tailroom before the copy
and skb_put(). Leave ownership of the management skb with the caller on
error, matching the existing rsi_send_beacon() cleanup path.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: rsi: validate beacon length before fixed buffer copy
rsi_prepare_beacon() copies the mac80211 beacon frame after
FRAME_DESC_SZ into a management skb whose usable tailroom may be smaller
than MAX_MGMT_PKT_SIZE after alignment.
Validate the beacon length against the actual tailroom before the copy
and skb_put(). Leave ownership of the management skb with the caller on
error, matching the existing rsi_send_beacon() cleanup path.
🎖@cveNotify
🚨 CVE-2026-93803
In the Linux kernel, the following vulnerability has been resolved:
wifi: libipw: fix key index receive bound checks
libipw_rx() reads skb->data[hdrlen + 3] to extract the WEP key index in
both the software-decrypt key selection path and the hardware-decrypted
IV/ICV strip path. In both places the existing guard only checks
skb->len >= hdrlen + 3, which proves bytes up to hdrlen + 2 but not the
byte at hdrlen + 3.
Require hdrlen + 4 bytes before reading that item in both paths. This is
a local source-boundary check only; it does not change the key index
semantics.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: libipw: fix key index receive bound checks
libipw_rx() reads skb->data[hdrlen + 3] to extract the WEP key index in
both the software-decrypt key selection path and the hardware-decrypted
IV/ICV strip path. In both places the existing guard only checks
skb->len >= hdrlen + 3, which proves bytes up to hdrlen + 2 but not the
byte at hdrlen + 3.
Require hdrlen + 4 bytes before reading that item in both paths. This is
a local source-boundary check only; it does not change the key index
semantics.
🎖@cveNotify
🚨 CVE-2026-93804
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: ibss: wait for in-flight TX on disconnect
While leaving an IBSS in ieee80211_ibss_disconnect() mac80211 flushes
stations, turns the carrier off and immediately tells the driver to
leave as well. While there may be synchronize_net() in station flush
and in this code later, packets can still be transmitted due to
cross-CPU race conditions after carrier off is set.
Therefore, it's possible for a race to happen where a TX to the
driver occurs while or after telling it to leave the IBSS. This can
be confusing to drivers, and in the case of iwlwifi leads to an
attempt to use invalid queues.
Move netif_carrier_off() to occur before sta_info_flush() during
IBSS disconnect, and add synchronize_net() if flushing didn't,
so that the synchronize_net() always happens between turning the
carrier off and telling the driver, avoiding this race.
🎖@cveNotify
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: ibss: wait for in-flight TX on disconnect
While leaving an IBSS in ieee80211_ibss_disconnect() mac80211 flushes
stations, turns the carrier off and immediately tells the driver to
leave as well. While there may be synchronize_net() in station flush
and in this code later, packets can still be transmitted due to
cross-CPU race conditions after carrier off is set.
Therefore, it's possible for a race to happen where a TX to the
driver occurs while or after telling it to leave the IBSS. This can
be confusing to drivers, and in the case of iwlwifi leads to an
attempt to use invalid queues.
Move netif_carrier_off() to occur before sta_info_flush() during
IBSS disconnect, and add synchronize_net() if flushing didn't,
so that the synchronize_net() always happens between turning the
carrier off and telling the driver, avoiding this race.
🎖@cveNotify