Linux: >> Linux Kernel >> 5.15.211 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: do not expire session on binding failure
When a multichannel session binding request fails (e.g. wrong password),
the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED.
However, during binding, sess points to the target session looked up via
ksmbd_session_lookup_slowpath() -- which belongs to another connection's
user. This allows a remote attacker to invalidate any active session by
simply sending a binding request with a wrong password (DoS).
Fix this by skipping session expiration when the failed request was
a binding attempt, since the session does not belong to the current
connection. The reference taken by ksmbd_session_lookup_slowpath() is
still correctly released via ksmbd_user_session_put().
CVSS Score
8.2
EPSS Score
0.005
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix memory leaks and NULL deref in smb2_lock()
smb2_lock() has three error handling issues after list_del() detaches
smb_lock from lock_list at no_check_cl:
1) If vfs_lock_file() returns an unexpected error in the non-UNLOCK
path, goto out leaks smb_lock and its flock because the out:
handler only iterates lock_list and rollback_list, neither of
which contains the detached smb_lock.
2) If vfs_lock_file() returns -ENOENT in the UNLOCK path, goto out
leaks smb_lock and flock for the same reason. The error code
returned to the dispatcher is also stale.
3) In the rollback path, smb_flock_init() can return NULL on
allocation failure. The result is dereferenced unconditionally,
causing a kernel NULL pointer dereference. Add a NULL check to
prevent the crash and clean up the bookkeeping; the VFS lock
itself cannot be rolled back without the allocation and will be
released at file or connection teardown.
Fix cases 1 and 2 by hoisting the locks_free_lock()/kfree() to before
the if(!rc) check in the UNLOCK branch so all exit paths share one
free site, and by freeing smb_lock and flock before goto out in the
non-UNLOCK branch. Propagate the correct error code in both cases.
Fix case 3 by wrapping the VFS unlock in an if(rlock) guard and adding
a NULL check for locks_free_lock(rlock) in the shared cleanup.
Found via call-graph analysis using sqry.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: prevent immediate PASID reuse case
PASID resue could cause interrupt issue when process
immediately runs into hw state left by previous
process exited with the same PASID, it's possible that
page faults are still pending in the IH ring buffer when
the process exits and frees up its PASID. To prevent the
case, it uses idr cyclic allocator same as kernel pid's.
(cherry picked from commit 8f1de51f49be692de137c8525106e0fce2d1912d)
CVSS Score
5.5
EPSS Score
0.001
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
ext4: replace BUG_ON with proper error handling in ext4_read_inline_folio
Replace BUG_ON() with proper error handling when inline data size
exceeds PAGE_SIZE. This prevents kernel panic and allows the system to
continue running while properly reporting the filesystem corruption.
The error is logged via ext4_error_inode(), the buffer head is released
to prevent memory leak, and -EFSCORRUPTED is returned to indicate
filesystem corruption.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
xfs: avoid dereferencing log items after push callbacks
After xfsaild_push_item() calls iop_push(), the log item may have been
freed if the AIL lock was dropped during the push. Background inode
reclaim or the dquot shrinker can free the log item while the AIL lock
is not held, and the tracepoints in the switch statement dereference
the log item after iop_push() returns.
Fix this by capturing the log item type, flags, and LSN before calling
xfsaild_push_item(), and introducing a new xfs_ail_push_class trace
event class that takes these pre-captured values and the ailp pointer
instead of the log item pointer.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid infinite loops caused by residual data
On the mkdir/mknod path, when mapping logical blocks to physical blocks,
if inserting a new extent into the extent tree fails (in this example,
because the file system disabled the huge file feature when marking the
inode as dirty), ext4_ext_map_blocks() only calls ext4_free_blocks() to
reclaim the physical block without deleting the corresponding data in
the extent tree. This causes subsequent mkdir operations to reference
the previously reclaimed physical block number again, even though this
physical block is already being used by the xattr block. Therefore, a
situation arises where both the directory and xattr are using the same
buffer head block in memory simultaneously.
The above causes ext4_xattr_block_set() to enter an infinite loop about
"inserted" and cannot release the inode lock, ultimately leading to the
143s blocking problem mentioned in [1].
If the metadata is corrupted, then trying to remove some extent space
can do even more harm. Also in case EXT4_GET_BLOCKS_DELALLOC_RESERVE
was passed, remove space wrongly update quota information.
Jan Kara suggests distinguishing between two cases:
1) The error is ENOSPC or EDQUOT - in this case the filesystem is fully
consistent and we must maintain its consistency including all the
accounting. However these errors can happen only early before we've
inserted the extent into the extent tree. So current code works correctly
for this case.
2) Some other error - this means metadata is corrupted. We should strive to
do as few modifications as possible to limit damage. So I'd just skip
freeing of allocated blocks.
[1]
INFO: task syz.0.17:5995 blocked for more than 143 seconds.
Call Trace:
inode_lock_nested include/linux/fs.h:1073 [inline]
__start_dirop fs/namei.c:2923 [inline]
start_dirop fs/namei.c:2934 [inline]
CVSS Score
9.4
EPSS Score
0.004
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
ext4: validate p_idx bounds in ext4_ext_correct_indexes
ext4_ext_correct_indexes() walks up the extent tree correcting
index entries when the first extent in a leaf is modified. Before
accessing path[k].p_idx->ei_block, there is no validation that
p_idx falls within the valid range of index entries for that
level.
If the on-disk extent header contains a corrupted or crafted
eh_entries value, p_idx can point past the end of the allocated
buffer, causing a slab-out-of-bounds read.
Fix this by validating path[k].p_idx against EXT_LAST_INDEX() at
both access sites: before the while loop and inside it. Return
-EFSCORRUPTED if the index pointer is out of range, consistent
with how other bounds violations are handled in the ext4 extent
tree code.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: idxd: Fix memory leak when a wq is reset
idxd_wq_disable_cleanup() which is called from the reset path for a
workqueue, sets the wq type to NONE, which for other parts of the
driver mean that the wq is empty (all its resources were released).
Only set the wq type to NONE after its resources are released.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix OOB write in QUERY_INFO for compound requests
When a compound request such as READ + QUERY_INFO(Security) is received,
and the first command (READ) consumes most of the response buffer,
ksmbd could write beyond the allocated buffer while building a security
descriptor.
The root cause was that smb2_get_info_sec() checked buffer space using
ppntsd_size from xattr, while build_sec_desc() often synthesized a
significantly larger descriptor from POSIX ACLs.
This patch introduces smb_acl_sec_desc_scratch_len() to accurately
compute the final descriptor size beforehand, performs proper buffer
checking with smb2_calc_max_out_buf_len(), and uses exact-sized
allocation + iov pinning.
CVSS Score
8.8
EPSS Score
0.005
Published
2026-04-22
In the Linux kernel, the following vulnerability has been resolved:
ACPI: EC: clean up handlers on probe failure in acpi_ec_setup()
When ec_install_handlers() returns -EPROBE_DEFER on reduced-hardware
platforms, it has already started the EC and installed the address
space handler with the struct acpi_ec pointer as handler context.
However, acpi_ec_setup() propagates the error without any cleanup.
The caller acpi_ec_add() then frees the struct acpi_ec for non-boot
instances, leaving a dangling handler context in ACPICA.
Any subsequent AML evaluation that accesses an EC OpRegion field
dispatches into acpi_ec_space_handler() with the freed pointer,
causing a use-after-free:
BUG: KASAN: slab-use-after-free in mutex_lock (kernel/locking/mutex.c:289)
Write of size 8 at addr ffff88800721de38 by task init/1
Call Trace:
<TASK>
mutex_lock (kernel/locking/mutex.c:289)
acpi_ec_space_handler (drivers/acpi/ec.c:1362)
acpi_ev_address_space_dispatch (drivers/acpi/acpica/evregion.c:293)
acpi_ex_access_region (drivers/acpi/acpica/exfldio.c:246)
acpi_ex_field_datum_io (drivers/acpi/acpica/exfldio.c:509)
acpi_ex_extract_from_field (drivers/acpi/acpica/exfldio.c:700)
acpi_ex_read_data_from_field (drivers/acpi/acpica/exfield.c:327)
acpi_ex_resolve_node_to_value (drivers/acpi/acpica/exresolv.c:392)
</TASK>
Allocated by task 1:
acpi_ec_alloc (drivers/acpi/ec.c:1424)
acpi_ec_add (drivers/acpi/ec.c:1692)
Freed by task 1:
kfree (mm/slub.c:6876)
acpi_ec_add (drivers/acpi/ec.c:1751)
The bug triggers on reduced-hardware EC platforms (ec->gpe < 0)
when the GPIO IRQ provider defers probing. Once the stale handler
exists, any unprivileged sysfs read that causes AML to touch an
EC OpRegion (battery, thermal, backlight) exercises the dangling
pointer.
Fix this by calling ec_remove_handlers() in the error path of
acpi_ec_setup() before clearing first_ec. ec_remove_handlers()
checks each EC_FLAGS_* bit before acting, so it is safe to call
regardless of how far ec_install_handlers() progressed:
-ENODEV (handler not installed): only calls acpi_ec_stop()
-EPROBE_DEFER (handler installed): removes handler, stops EC
CVSS Score
7.0
EPSS Score
0.001
Published
2026-04-13