Linux: >> Linux Kernel >> 5.10.255 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix in-place encryption corruption in SMB2_write()
SMB2_write() places write payload in iov[1..n] as part of rq_iov.
smb3_init_transform_rq() pointer-shares rq_iov, so crypt_message()
encrypts iov[1] in-place, replacing the original plaintext with
ciphertext. On a replayable error, the retry sends the same iov[1]
which now contains ciphertext instead of the original data,
resulting in corruption.
The corruption is most likely to be observed when connections are
unstable, as reconnects trigger write retries that re-send the
already-encrypted data.
This affects SFU mknod, MF symlinks, etc. On kernels before
6.10 (prior to the netfs conversion), sync writes also used
this path and were similarly affected. The async write path
wasn't unaffected as it uses rq_iter which gets deep-copied.
Fix by moving the write payload into rq_iter via iov_iter_kvec(),
so smb3_init_transform_rq() deep-copies it before encryption.
CVSS Score
8.1
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix transaction abort on set received ioctl due to item overflow
If the set received ioctl fails due to an item overflow when attempting to
add the BTRFS_UUID_KEY_RECEIVED_SUBVOL we have to abort the transaction
since we did some metadata updates before.
This means that if a user calls this ioctl with the same received UUID
field for a lot of subvolumes, we will hit the overflow, trigger the
transaction abort and turn the filesystem into RO mode. A malicious user
could exploit this, and this ioctl does not even requires that a user
has admin privileges (CAP_SYS_ADMIN), only that he/she owns the subvolume.
Fix this by doing an early check for item overflow before starting a
transaction. This is also race safe because we are holding the subvol_sem
semaphore in exclusive (write) mode.
A test case for fstests will follow soon.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix transaction abort when snapshotting received subvolumes
Currently a user can trigger a transaction abort by snapshotting a
previously received snapshot a bunch of times until we reach a
BTRFS_UUID_KEY_RECEIVED_SUBVOL item overflow (the maximum item size we
can store in a leaf). This is very likely not common in practice, but
if it happens, it turns the filesystem into RO mode. The snapshot, send
and set_received_subvol and subvol_setflags (used by receive) don't
require CAP_SYS_ADMIN, just inode_owner_or_capable(). A malicious user
could use this to turn a filesystem into RO mode and disrupt a system.
Reproducer script:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdi
MNT=/mnt/sdi
# Use smallest node size to make the test faster.
mkfs.btrfs -f --nodesize 4K $DEV
mount $DEV $MNT
# Create a subvolume and set it to RO so that it can be used for send.
btrfs subvolume create $MNT/sv
touch $MNT/sv/foo
btrfs property set $MNT/sv ro true
# Send and receive the subvolume into snaps/sv.
mkdir $MNT/snaps
btrfs send $MNT/sv | btrfs receive $MNT/snaps
# Now snapshot the received subvolume, which has a received_uuid, a
# lot of times to trigger the leaf overflow.
total=500
for ((i = 1; i <= $total; i++)); do
echo -ne "\rCreating snapshot $i/$total"
btrfs subvolume snapshot -r $MNT/snaps/sv $MNT/snaps/sv_$i > /dev/null
done
echo
umount $MNT
When running the test:
$ ./test.sh
(...)
Create subvolume '/mnt/sdi/sv'
At subvol /mnt/sdi/sv
At subvol sv
Creating snapshot 496/500ERROR: Could not create subvolume: Value too large for defined data type
Creating snapshot 497/500ERROR: Could not create subvolume: Read-only file system
Creating snapshot 498/500ERROR: Could not create subvolume: Read-only file system
Creating snapshot 499/500ERROR: Could not create subvolume: Read-only file system
Creating snapshot 500/500ERROR: Could not create subvolume: Read-only file system
And in dmesg/syslog:
$ dmesg
(...)
[251067.627338] BTRFS warning (device sdi): insert uuid item failed -75 (0x4628b21c4ac8d898, 0x2598bee2b1515c91) type 252!
[251067.629212] ------------[ cut here ]------------
[251067.630033] BTRFS: Transaction aborted (error -75)
[251067.630871] WARNING: fs/btrfs/transaction.c:1907 at create_pending_snapshot.cold+0x52/0x465 [btrfs], CPU#10: btrfs/615235
[251067.632851] Modules linked in: btrfs dm_zero (...)
[251067.644071] CPU: 10 UID: 0 PID: 615235 Comm: btrfs Tainted: G W 6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
[251067.646165] Tainted: [W]=WARN
[251067.646733] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[251067.648735] RIP: 0010:create_pending_snapshot.cold+0x55/0x465 [btrfs]
[251067.649984] Code: f0 48 0f (...)
[251067.653313] RSP: 0018:ffffce644908fae8 EFLAGS: 00010292
[251067.653987] RAX: 00000000ffffff01 RBX: ffff8e5639e63a80 RCX: 00000000ffffffd3
[251067.655042] RDX: ffff8e53faa76b00 RSI: 00000000ffffffb5 RDI: ffffffffc0919750
[251067.656077] RBP: ffffce644908fbd8 R08: 0000000000000000 R09: ffffce644908f820
[251067.657068] R10: ffff8e5adc1fffa8 R11: 0000000000000003 R12: ffff8e53c0431bd0
[251067.658050] R13: ffff8e5414593600 R14: ffff8e55efafd000 R15: 00000000ffffffb5
[251067.659019] FS: 00007f2a4944b3c0(0000) GS:ffff8e5b27dae000(0000) knlGS:0000000000000000
[251067.660115] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[251067.660943] CR2: 00007ffc5aa57898 CR3: 00000005813a2003 CR4: 0000000000370ef0
[251067.661972] Call Trace:
[251067.662292] <TASK>
[251067.662653] create_pending_snapshots+0x97/0xc0 [btrfs]
[251067.663413] btrfs_commit_transaction+0x26e/0xc00 [btrfs]
[251067.664257] ? btrfs_qgroup_convert_reserved_meta+0x35/0x390 [btrfs]
[251067.665238] ? _raw_spin_unlock+0x15/0x30
[251067.665837] ? record_root_
---truncated---
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
smb: client: require a full NFS mode SID before reading mode bits
parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS
mode SID and reads sid.sub_auth[2] to recover the mode bits.
That assumes the ACE carries three subauthorities, but compare_sids()
only compares min(a, b) subauthorities. A malicious server can return
an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still
matches sid_unix_NFS_mode and then drives the sub_auth[2] read four
bytes past the end of the ACE.
Require num_subauth >= 3 before treating the ACE as an NFS mode SID.
This keeps the fix local to the special-SID mode path without changing
compare_sids() semantics for the rest of cifsacl.
CVSS Score
7.6
EPSS Score
0.001
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
btrfs: reserve enough transaction items for qgroup ioctls
Currently our qgroup ioctls don't reserve any space, they just do a
transaction join, which does not reserve any space, neither for the quota
tree updates nor for the delayed refs generated when updating the quota
tree. The quota root uses the global block reserve, which is fine most of
the time since we don't expect a lot of updates to the quota root, or to
be too close to -ENOSPC such that other critical metadata updates need to
resort to the global reserve.
However this is not optimal, as not reserving proper space may result in a
transaction abort due to not reserving space for delayed refs and then
abusing the use of the global block reserve.
For example, the following reproducer (which is unlikely to model any
real world use case, but just to illustrate the problem), triggers such a
transaction abort due to -ENOSPC when running delayed refs:
$ cat test.sh
#!/bin/bash
DEV=/dev/nullb0
MNT=/mnt/nullb0
umount $DEV &> /dev/null
# Limit device to 1G so that it's much faster to reproduce the issue.
mkfs.btrfs -f -b 1G $DEV
mount -o commit=600 $DEV $MNT
fallocate -l 800M $MNT/filler
btrfs quota enable $MNT
for ((i = 1; i <= 400000; i++)); do
btrfs qgroup create 1/$i $MNT
done
umount $MNT
When running this, we can see in dmesg/syslog that a transaction abort
happened:
[436.490] BTRFS error (device nullb0): failed to run delayed ref for logical 30408704 num_bytes 16384 type 176 action 1 ref_mod 1: -28
[436.493] ------------[ cut here ]------------
[436.494] BTRFS: Transaction aborted (error -28)
[436.495] WARNING: fs/btrfs/extent-tree.c:2247 at btrfs_run_delayed_refs+0xd9/0x110 [btrfs], CPU#4: umount/2495372
[436.497] Modules linked in: btrfs loop (...)
[436.508] CPU: 4 UID: 0 PID: 2495372 Comm: umount Tainted: G W 6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
[436.510] Tainted: [W]=WARN
[436.511] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[436.513] RIP: 0010:btrfs_run_delayed_refs+0xdf/0x110 [btrfs]
[436.514] Code: 0f 82 ea (...)
[436.518] RSP: 0018:ffffd511850b7d78 EFLAGS: 00010292
[436.519] RAX: 00000000ffffffe4 RBX: ffff8f120dad37e0 RCX: 0000000002040001
[436.520] RDX: 0000000000000002 RSI: 00000000ffffffe4 RDI: ffffffffc090fd80
[436.522] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffffc04d1867
[436.523] R10: ffff8f18dc1fffa8 R11: 0000000000000003 R12: ffff8f173aa89400
[436.524] R13: 0000000000000000 R14: ffff8f173aa89400 R15: 0000000000000000
[436.526] FS: 00007fe59045d840(0000) GS:ffff8f192e22e000(0000) knlGS:0000000000000000
[436.527] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[436.528] CR2: 00007fe5905ff2b0 CR3: 000000060710a002 CR4: 0000000000370ef0
[436.530] Call Trace:
[436.530] <TASK>
[436.530] btrfs_commit_transaction+0x73/0xc00 [btrfs]
[436.531] ? btrfs_attach_transaction_barrier+0x1e/0x70 [btrfs]
[436.532] sync_filesystem+0x7a/0x90
[436.533] generic_shutdown_super+0x28/0x180
[436.533] kill_anon_super+0x12/0x40
[436.534] btrfs_kill_super+0x12/0x20 [btrfs]
[436.534] deactivate_locked_super+0x2f/0xb0
[436.534] cleanup_mnt+0xea/0x180
[436.535] task_work_run+0x58/0xa0
[436.535] exit_to_user_mode_loop+0xed/0x480
[436.536] ? __x64_sys_umount+0x68/0x80
[436.536] do_syscall_64+0x2a5/0xf20
[436.537] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[436.537] RIP: 0033:0x7fe5906b6217
[436.538] Code: 0d 00 f7 (...)
[436.540] RSP: 002b:00007ffcd87a61f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[436.541] RAX: 0000000000000000 RBX: 00005618b9ecadc8 RCX: 00007fe5906b6217
[436.541] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005618b9ecb100
[436.542] RBP: 0000000000000000 R08: 00007ffcd87a4fe0 R09: 00000000ffffffff
[436.544] R10: 0000000000000103 R11:
---truncated---
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
netfilter: flowtable: strictly check for maximum number of actions
The maximum number of flowtable hardware offload actions in IPv6 is:
* ethernet mangling (4 payload actions, 2 for each ethernet address)
* SNAT (4 payload actions)
* DNAT (4 payload actions)
* Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing)
for QinQ.
* Redirect (1 action)
Which makes 17, while the maximum is 16. But act_ct supports for tunnels
actions too. Note that payload action operates at 32-bit word level, so
mangling an IPv6 address takes 4 payload actions.
Update flow_action_entry_next() calls to check for the maximum number of
supported actions.
While at it, rise the maximum number of actions per flow from 16 to 24
so this works fine with IPv6 setups.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
most: core: fix leak on early registration failure
A recent commit fixed a resource leak on early registration failures but
for some reason left out the first error path which still leaks the
resources associated with the interface.
Fix up also the first error path so that the interface is always
released on errors.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix sync handling in amdgpu_dma_buf_move_notify
Invalidating a dmabuf will impact other users of the shared BO.
In the scenario where process A moves the BO, it needs to inform
process B about the move and process B will need to update its
page table.
The commit fixes a synchronisation bug caused by the use of the
ticket: it made amdgpu_vm_handle_moved behave as if updating
the page table immediately was correct but in this case it's not.
An example is the following scenario, with 2 GPUs and glxgears
running on GPU0 and Xorg running on GPU1, on a system where P2P
PCI isn't supported:
glxgears:
export linear buffer from GPU0 and import using GPU1
submit frame rendering to GPU0
submit tiled->linear blit
Xorg:
copy of linear buffer
The sequence of jobs would be:
drm_sched_job_run # GPU0, frame rendering
drm_sched_job_queue # GPU0, blit
drm_sched_job_done # GPU0, frame rendering
drm_sched_job_run # GPU0, blit
move linear buffer for GPU1 access #
amdgpu_dma_buf_move_notify -> update pt # GPU0
It this point the blit job on GPU0 is still running and would
likely produce a page fault.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()
In acpi_processor_errata_piix4(), the pointer dev is first assigned an IDE
device and then reassigned an ISA device:
dev = pci_get_subsys(..., PCI_DEVICE_ID_INTEL_82371AB, ...);
dev = pci_get_subsys(..., PCI_DEVICE_ID_INTEL_82371AB_0, ...);
If the first lookup succeeds but the second fails, dev becomes NULL. This
leads to a potential null-pointer dereference when dev_dbg() is called:
if (errata.piix4.bmisx)
dev_dbg(&dev->dev, ...);
To prevent this, use two temporary pointers and retrieve each device
independently, avoiding overwriting dev with a possible NULL value.
[ rjw: Subject adjustment, added an empty code line ]
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't BUG() on unexpected delayed ref type in run_one_delayed_ref()
There is no need to BUG(), we can just return an error and log an error
message.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-08