Linux: >> Linux Kernel >> 5.15.7 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
nfsd: never defer requests during idmap lookup
During v4 request compound arg decoding, some ops (e.g. SETATTR)
can trigger idmap lookup upcalls. When those upcall responses get
delayed beyond the allowed time limit, cache_check() will mark the
request for deferral and cause it to be dropped.
This prevents nfs4svc_encode_compoundres from being executed, and
thus the session slot flag NFSD4_SLOT_INUSE never gets cleared.
Subsequent client requests will fail with NFSERR_JUKEBOX, given
that the slot will be marked as in-use, making the SEQUENCE op
fail.
Fix this by making sure that the RQ_USEDEFERRAL flag is always
clear during nfs4svc_decode_compoundargs(), since no v4 request
should ever be deferred.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Fix use-after-free in iomap inline data write path
The inline data buffer head (dibh) is being released prematurely in
gfs2_iomap_begin() via release_metapath() while iomap->inline_data
still points to dibh->b_data. This causes a use-after-free when
iomap_write_end_inline() later attempts to write to the inline data
area.
The bug sequence:
1. gfs2_iomap_begin() calls gfs2_meta_inode_buffer() to read inode
metadata into dibh
2. Sets iomap->inline_data = dibh->b_data + sizeof(struct gfs2_dinode)
3. Calls release_metapath() which calls brelse(dibh), dropping refcount
to 0
4. kswapd reclaims the page (~39ms later in the syzbot report)
5. iomap_write_end_inline() tries to memcpy() to iomap->inline_data
6. KASAN detects use-after-free write to freed memory
Fix by storing dibh in iomap->private and incrementing its refcount
with get_bh() in gfs2_iomap_begin(). The buffer is then properly
released in gfs2_iomap_end() after the inline write completes,
ensuring the page stays alive for the entire iomap operation.
Note: A C reproducer is not available for this issue. The fix is based
on analysis of the KASAN report and code review showing the buffer head
is freed before use.
[agruenba: Take buffer head reference in gfs2_iomap_begin() to avoid
leaks in gfs2_iomap_get() and gfs2_iomap_alloc().]
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
ext4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O
When allocating blocks during within-EOF DIO and writeback with
dioread_nolock enabled, EXT4_GET_BLOCKS_PRE_IO was set to split an
existing large unwritten extent. However, EXT4_GET_BLOCKS_CONVERT was
set when calling ext4_split_convert_extents(), which may potentially
result in stale data issues.
Assume we have an unwritten extent, and then DIO writes the second half.
[UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent
[UUUUUUUUUUUUUUUU] extent status tree
|<- ->| ----> dio write this range
First, ext4_iomap_alloc() call ext4_map_blocks() with
EXT4_GET_BLOCKS_PRE_IO, EXT4_GET_BLOCKS_UNWRIT_EXT and
EXT4_GET_BLOCKS_CREATE flags set. ext4_map_blocks() find this extent and
call ext4_split_convert_extents() with EXT4_GET_BLOCKS_CONVERT and the
above flags set.
Then, ext4_split_convert_extents() calls ext4_split_extent() with
EXT4_EXT_MAY_ZEROOUT, EXT4_EXT_MARK_UNWRIT2 and EXT4_EXT_DATA_VALID2
flags set, and it calls ext4_split_extent_at() to split the second half
with EXT4_EXT_DATA_VALID2, EXT4_EXT_MARK_UNWRIT1, EXT4_EXT_MAY_ZEROOUT
and EXT4_EXT_MARK_UNWRIT2 flags set. However, ext4_split_extent_at()
failed to insert extent since a temporary lack -ENOSPC. It zeroes out
the first half but convert the entire on-disk extent to written since
the EXT4_EXT_DATA_VALID2 flag set, but left the second half as unwritten
in the extent status tree.
[0000000000SSSSSS] data S: stale data, 0: zeroed
[WWWWWWWWWWWWWWWW] on-disk extent W: written extent
[WWWWWWWWWWUUUUUU] extent status tree
Finally, if the DIO failed to write data to the disk, the stale data in
the second half will be exposed once the cached extent entry is gone.
Fix this issue by not passing EXT4_GET_BLOCKS_CONVERT when splitting
an unwritten extent before submitting I/O, and make
ext4_split_convert_extents() to zero out the entire extent range
to zero for this case, and also mark the extent in the extent status
tree for consistency.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
crypto: ccree - fix a memory leak in cc_mac_digest()
Add cc_unmap_result() if cc_map_hash_request_final()
fails to prevent potential memory leak.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not found
If btrfs_search_slot_for_read() returns 1, it means we did not find any
key greater than or equals to the key we asked for, meaning we have
reached the end of the tree and therefore the path is not valid. If
this happens we need to break out of the loop and stop, instead of
continuing and accessing an invalid path.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
staging: greybus: lights: avoid NULL deref
gb_lights_light_config() stores channel_count before allocating the
channels array. If kcalloc() fails, gb_lights_release() iterates the
non-zero count and dereferences light->channels, which is NULL.
Allocate channels first and only then publish channels_count so the
cleanup path can't walk a NULL pointer.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: fix gss_auth kref leak in gss_alloc_msg error path
Commit 5940d1cf9f42 ("SUNRPC: Rebalance a kref in auth_gss.c") added
a kref_get(&gss_auth->kref) call to balance the gss_put_auth() done
in gss_release_msg(), but forgot to add a corresponding kref_put()
on the error path when kstrdup_const() fails.
If service_name is non-NULL and kstrdup_const() fails, the function
jumps to err_put_pipe_version which calls put_pipe_version() and
kfree(gss_msg), but never releases the gss_auth reference. This leads
to a kref leak where the gss_auth structure is never freed.
Add a forward declaration for gss_free_callback() and call kref_put()
in the err_put_pipe_version error path to properly release the
reference taken earlier.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix invalid deref of rawdata when export_binary is unset
If the export_binary parameter is disabled on runtime, profiles that
were loaded before that will still have their rawdata stored in
apparmorfs, with a symbolic link to the rawdata on the policy
directory. When one of those profiles are replaced, the rawdata is set
to NULL, but when trying to resolve the symbolic links to rawdata for
that profile, it will try to dereference profile->rawdata->name when
profile->rawdata is now NULL causing an oops. Fix it by checking if
rawdata is set.
[ 168.653080] BUG: kernel NULL pointer dereference, address: 0000000000000088
[ 168.657420] #PF: supervisor read access in kernel mode
[ 168.660619] #PF: error_code(0x0000) - not-present page
[ 168.663613] PGD 0 P4D 0
[ 168.665450] Oops: Oops: 0000 [#1] SMP NOPTI
[ 168.667836] CPU: 1 UID: 0 PID: 1729 Comm: ls Not tainted 6.19.0-rc7+ #3 PREEMPT(voluntary)
[ 168.672308] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 168.679327] RIP: 0010:rawdata_get_link_base.isra.0+0x23/0x330
[ 168.682768] Code: 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 18 48 89 55 d0 48 85 ff 0f 84 e3 01 00 00 <48> 83 3c 25 88 00 00 00 00 0f 84 d4 01 00 00 49 89 f6 49 89 cc e8
[ 168.689818] RSP: 0018:ffffcdcb8200fb80 EFLAGS: 00010282
[ 168.690871] RAX: ffffffffaee74ec0 RBX: 0000000000000000 RCX: ffffffffb0120158
[ 168.692251] RDX: ffffcdcb8200fbe0 RSI: ffff88c187c9fa80 RDI: ffff88c186c98a80
[ 168.693593] RBP: ffffcdcb8200fbc0 R08: 0000000000000000 R09: 0000000000000000
[ 168.694941] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88c186c98a80
[ 168.696289] R13: 00007fff005aaa20 R14: 0000000000000080 R15: ffff88c188f4fce0
[ 168.697637] FS: 0000790e81c58280(0000) GS:ffff88c20a957000(0000) knlGS:0000000000000000
[ 168.699227] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 168.700349] CR2: 0000000000000088 CR3: 000000012fd3e000 CR4: 0000000000350ef0
[ 168.701696] Call Trace:
[ 168.702325] <TASK>
[ 168.702995] rawdata_get_link_data+0x1c/0x30
[ 168.704145] vfs_readlink+0xd4/0x160
[ 168.705152] do_readlinkat+0x114/0x180
[ 168.706214] __x64_sys_readlink+0x1e/0x30
[ 168.708653] x64_sys_call+0x1d77/0x26b0
[ 168.709525] do_syscall_64+0x81/0x500
[ 168.710348] ? do_statx+0x72/0xb0
[ 168.711109] ? putname+0x3e/0x80
[ 168.711845] ? __x64_sys_statx+0xb7/0x100
[ 168.712711] ? x64_sys_call+0x10fc/0x26b0
[ 168.713577] ? do_syscall_64+0xbf/0x500
[ 168.714412] ? do_user_addr_fault+0x1d2/0x8d0
[ 168.715404] ? irqentry_exit+0xb2/0x740
[ 168.716359] ? exc_page_fault+0x90/0x1b0
[ 168.717307] entry_SYSCALL_64_after_hwframe+0x76/0x7e
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
cpuidle: Skip governor when only one idle state is available
On certain platforms (PowerNV systems without a power-mgt DT node),
cpuidle may register only a single idle state. In cases where that
single state is a polling state (state 0), the ladder governor may
incorrectly treat state 1 as the first usable state and pass an
out-of-bounds index. This can lead to a NULL enter callback being
invoked, ultimately resulting in a system crash.
[ 13.342636] cpuidle-powernv : Only Snooze is available
[ 13.351854] Faulting instruction address: 0x00000000
[ 13.376489] NIP [0000000000000000] 0x0
[ 13.378351] LR [c000000001e01974] cpuidle_enter_state+0x2c4/0x668
Fix this by adding a bail-out in cpuidle_select() that returns state 0
directly when state_count <= 1, bypassing the governor and keeping the
tick running.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
HID: playstation: Add missing check for input_ff_create_memless
The ps_gamepad_create() function calls input_ff_create_memless()
without verifying its return value, which can lead to incorrect
behavior or potential crashes when FF effects are triggered.
Add a check for the return value of input_ff_create_memless().
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-27