Linux: >> Linux Kernel >> 3.4.45 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Add missing save/restore handling of LBR MSRs
MSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by
KVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So
save/restore is completely broken.
Fix it by adding the MSRs to msrs_to_save_base, and allowing writes to
LBR MSRs from userspace only (as they are read-only MSRs) if LBR
virtualization is enabled. Additionally, to correctly restore L1's LBRs
while L2 is running, make sure the LBRs are copied from the captured
VMCB01 save area in svm_copy_vmrun_state().
Note, for VMX, this also fixes a flaw where MSR_IA32_DEBUGCTLMSR isn't
reported as an MSR to save/restore.
Note #2, over-reporting MSR_IA32_LASTxxx on Intel is ok, as KVM already
handles unsupported reads and writes thanks to commit b5e2fec0ebc3 ("KVM:
Ignore DEBUGCTL MSRs with no effect") (kvm_do_msr_access() will morph the
unsupported userspace write into a nop).
[sean: guard with lbrv checks, massage changelog]
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
ALSA: caiaq: Handle probe errors properly
The probe procedure of setup_card() in caiaq driver doesn't treat the
error cases gracefully, e.g. the error from snd_card_register() calls
snd_card_free() but continues. This would lead to a UAF for the
further calls like snd_usb_caiaq_control_init(), as Berk suggested in
another patch in the link below.
However, the problem is not only that; in general, this function drops
the all error handlings (as it's a void function) although its caller
can propagate an error to snd_probe(), which eventually calls
snd_card_free() as a proper error path. That said, we should treat
each error case in setup_card(), and just return the error code
promptly, which is then handled later as a fatal error in snd_probe().
This patch achieves it by changing the setup_card() to return an error
code. Also, the superfluous snd_card_free() call is removed, too.
Note that card->private_free can be set still safely at returning an
error. All called functions in card_free() have checks of the
unassigned resources or NULL checks.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: fix u32 overflow in pushbuf reloc bounds check
nouveau_gem_pushbuf_reloc_apply() validates each relocation with
if (r->reloc_bo_offset + 4 > nvbo->bo.base.size)
but reloc_bo_offset is __u32 (uapi/drm/nouveau_drm.h) and the integer
literal 4 promotes to unsigned int, so the addition is performed in 32
bits and wraps before the comparison against the size_t bo size.
Cast to u64 so the addition happens in 64-bit arithmetic.
[ Add Fixes: tag. - Danilo ]
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix conn-level packet handling to unshare RESPONSE packets
The security operations that verify the RESPONSE packets decrypt bits of it
in place - however, the sk_buff may be shared with a packet sniffer, which
would lead to the sniffer seeing an apparently corrupt packet (actually
decrypted).
Fix this by handing a copy of the packet off to the specific security
handler if the packet was cloned.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
ext2: reject inodes with zero i_nlink and valid mode in ext2_iget()
ext2_iget() already rejects inodes with i_nlink == 0 when i_mode is
zero or i_dtime is set, treating them as deleted. However, the case of
i_nlink == 0 with a non-zero mode and zero dtime slips through. Since
ext2 has no orphan list, such a combination can only result from
filesystem corruption - a legitimate inode deletion always sets either
i_dtime or clears i_mode before freeing the inode.
A crafted image can exploit this gap to present such an inode to the
VFS, which then triggers WARN_ON inside drop_nlink() (fs/inode.c) via
ext2_unlink(), ext2_rename() and ext2_rmdir():
WARNING: CPU: 3 PID: 609 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336
CPU: 3 UID: 0 PID: 609 Comm: syz-executor Not tainted 6.12.77+ #1
Call Trace:
<TASK>
inode_dec_link_count include/linux/fs.h:2518 [inline]
ext2_unlink+0x26c/0x300 fs/ext2/namei.c:295
vfs_unlink+0x2fc/0x9b0 fs/namei.c:4477
do_unlinkat+0x53e/0x730 fs/namei.c:4541
__x64_sys_unlink+0xc6/0x110 fs/namei.c:4587
do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
WARNING: CPU: 0 PID: 646 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336
CPU: 0 UID: 0 PID: 646 Comm: syz.0.17 Not tainted 6.12.77+ #1
Call Trace:
<TASK>
inode_dec_link_count include/linux/fs.h:2518 [inline]
ext2_rename+0x35e/0x850 fs/ext2/namei.c:374
vfs_rename+0xf2f/0x2060 fs/namei.c:5021
do_renameat2+0xbe2/0xd50 fs/namei.c:5178
__x64_sys_rename+0x7e/0xa0 fs/namei.c:5223
do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
WARNING: CPU: 0 PID: 634 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336
CPU: 0 UID: 0 PID: 634 Comm: syz-executor Not tainted 6.12.77+ #1
Call Trace:
<TASK>
inode_dec_link_count include/linux/fs.h:2518 [inline]
ext2_rmdir+0xca/0x110 fs/ext2/namei.c:311
vfs_rmdir+0x204/0x690 fs/namei.c:4348
do_rmdir+0x372/0x3e0 fs/namei.c:4407
__x64_sys_unlinkat+0xf0/0x130 fs/namei.c:4577
do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Extend the existing i_nlink == 0 check to also catch this case,
reporting the corruption via ext2_error() and returning -EFSCORRUPTED.
This rejects the inode at load time and prevents it from reaching any
of the namei.c paths.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix re-decryption of RESPONSE packets
If a RESPONSE packet gets a temporary failure during processing, it may end
up in a partially decrypted state - and then get requeued for a retry.
Fix this by just discarding the packet; we will send another CHALLENGE
packet and thereby elicit a further response. Similarly, discard an
incoming CHALLENGE packet if we get an error whilst generating a RESPONSE;
the server will send another CHALLENGE.
CVSS Score
9.8
EPSS Score
0.005
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
ibmasm: fix OOB reads in command_file_write due to missing size checks
The command_file_write() handler allocates a kernel buffer of exactly
count bytes and copies user data into it, but does not validate the
buffer against the dot command protocol before passing it to
get_dot_command_size() and get_dot_command_timeout().
Since both the allocation size (count) and the header fields (command_size,
data_size) are independently user-controlled, an attacker can cause
get_dot_command_size() to return a value exceeding the allocation,
triggering OOB reads in get_dot_command_timeout() and an out-of-bounds
memcpy_toio() that leaks kernel heap memory to the service processor.
Fix with two guards: reject writes smaller than sizeof(struct
dot_command_header) before allocation, then after copying user data
reject commands where the buffer is smaller than the total size declared
by the header (sizeof(header) + command_size + data_size). This ensures
all subsequent header and payload field accesses stay within the buffer.
CVSS Score
7.1
EPSS Score
0.002
Published
2026-05-27
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:
bonding: alb: fix UAF in rlb_arp_recv during bond up/down
The ALB RX path may access rx_hashtbl concurrently with bond
teardown. During rapid bond up/down cycles, rlb_deinitialize()
frees rx_hashtbl while RX handlers are still running, leading
to a null pointer dereference detected by KASAN.
However, the root cause is that rlb_arp_recv() can still be accessed
after setting recv_probe to NULL, which is actually a use-after-free
(UAF) issue. That is the reason for using the referenced commit in the
Fixes tag.
[ 214.174138] Oops: general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] SMP KASAN PTI
[ 214.186478] KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
[ 214.194933] CPU: 30 UID: 0 PID: 2375 Comm: ping Kdump: loaded Not tainted 6.19.0-rc8+ #2 PREEMPT(voluntary)
[ 214.205907] Hardware name: Dell Inc. PowerEdge R730/0WCJNT, BIOS 2.14.0 01/14/2022
[ 214.214357] RIP: 0010:rlb_arp_recv+0x505/0xab0 [bonding]
[ 214.220320] Code: 0f 85 2b 05 00 00 48 b8 00 00 00 00 00 fc ff df 40 0f b6 ed 48 c1 e5 06 49 03 ad 78 01 00 00 48 8d 7d 28 48 89 fa 48 c1 ea 03 <0f> b6
04 02 84 c0 74 06 0f 8e 12 05 00 00 80 7d 28 00 0f 84 8c 00
[ 214.241280] RSP: 0018:ffffc900073d8870 EFLAGS: 00010206
[ 214.247116] RAX: dffffc0000000000 RBX: ffff888168556822 RCX: ffff88816855681e
[ 214.255082] RDX: 000000000000001d RSI: dffffc0000000000 RDI: 00000000000000e8
[ 214.263048] RBP: 00000000000000c0 R08: 0000000000000002 R09: ffffed11192021c8
[ 214.271013] R10: ffff8888c9010e43 R11: 0000000000000001 R12: 1ffff92000e7b119
[ 214.278978] R13: ffff8888c9010e00 R14: ffff888168556822 R15: ffff888168556810
[ 214.286943] FS: 00007f85d2d9cb80(0000) GS:ffff88886ccb3000(0000) knlGS:0000000000000000
[ 214.295966] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 214.302380] CR2: 00007f0d047b5e34 CR3: 00000008a1c2e002 CR4: 00000000001726f0
[ 214.310347] Call Trace:
[ 214.313070] <IRQ>
[ 214.315318] ? __pfx_rlb_arp_recv+0x10/0x10 [bonding]
[ 214.320975] bond_handle_frame+0x166/0xb60 [bonding]
[ 214.326537] ? __pfx_bond_handle_frame+0x10/0x10 [bonding]
[ 214.332680] __netif_receive_skb_core.constprop.0+0x576/0x2710
[ 214.339199] ? __pfx_arp_process+0x10/0x10
[ 214.343775] ? sched_balance_find_src_group+0x98/0x630
[ 214.349513] ? __pfx___netif_receive_skb_core.constprop.0+0x10/0x10
[ 214.356513] ? arp_rcv+0x307/0x690
[ 214.360311] ? __pfx_arp_rcv+0x10/0x10
[ 214.364499] ? __lock_acquire+0x58c/0xbd0
[ 214.368975] __netif_receive_skb_one_core+0xae/0x1b0
[ 214.374518] ? __pfx___netif_receive_skb_one_core+0x10/0x10
[ 214.380743] ? lock_acquire+0x10b/0x140
[ 214.385026] process_backlog+0x3f1/0x13a0
[ 214.389502] ? process_backlog+0x3aa/0x13a0
[ 214.394174] __napi_poll.constprop.0+0x9f/0x370
[ 214.399233] net_rx_action+0x8c1/0xe60
[ 214.403423] ? __pfx_net_rx_action+0x10/0x10
[ 214.408193] ? lock_acquire.part.0+0xbd/0x260
[ 214.413058] ? sched_clock_cpu+0x6c/0x540
[ 214.417540] ? mark_held_locks+0x40/0x70
[ 214.421920] handle_softirqs+0x1fd/0x860
[ 214.426302] ? __pfx_handle_softirqs+0x10/0x10
[ 214.431264] ? __neigh_event_send+0x2d6/0xf50
[ 214.436131] do_softirq+0xb1/0xf0
[ 214.439830] </IRQ>
The issue is reproducible by repeatedly running
ip link set bond0 up/down while receiving ARP messages, where
rlb_arp_recv() can race with rlb_deinitialize() and dereference
a freed rx_hashtbl entry.
Fix this by setting recv_probe to NULL and then calling
synchronize_net() to wait for any concurrent RX processing to finish.
This ensures that no RX handler can access rx_hashtbl after it is freed
in bond_alb_deinitialize().
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
drm/exynos: vidi: fix to avoid directly dereferencing user pointer
In vidi_connection_ioctl(), vidi->edid(user pointer) is directly
dereferenced in the kernel.
This allows arbitrary kernel memory access from the user space, so instead
of directly accessing the user pointer in the kernel, we should modify it
to copy edid to kernel memory using copy_from_user() and use it.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-05-27