Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path
icmp_route_lookup() performs multiple route lookups to find a suitable
route for sending ICMP error messages, with special handling for XFRM
(IPsec) policies.
The lookup sequence is:
1. First, lookup output route for ICMP reply (dst = original src)
2. Pass through xfrm_lookup() for policy check
3. If blocked (-EPERM) or dst is not local, enter "reverse path"
4. In reverse path, call xfrm_decode_session_reverse() to get fl4_dec
which reverses the original packet's flow (saddr<->daddr swapped)
5. If fl4_dec.saddr is local (we are the original destination), use
__ip_route_output_key() for output route lookup
6. If fl4_dec.saddr is NOT local (we are a forwarding node), use
ip_route_input() to simulate the reverse packet's input path
7. Finally, pass rt2 through xfrm_lookup() with XFRM_LOOKUP_ICMP flag
The bug occurs in step 6: ip_route_input() is called with fl4_dec.daddr
(original packet's source) as destination. If this address becomes local
between the initial check and ip_route_input() call (e.g., due to
concurrent "ip addr add"), ip_route_input() returns a LOCAL route with
dst.output set to ip_rt_bug.
This route is then used for ICMP output, causing dst_output() to call
ip_rt_bug(), triggering a WARN_ON:
------------[ cut here ]------------
WARNING: net/ipv4/route.c:1275 at ip_rt_bug+0x21/0x30, CPU#1
Call Trace:
<TASK>
ip_push_pending_frames+0x202/0x240
icmp_push_reply+0x30d/0x430
__icmp_send+0x1149/0x24f0
ip_options_compile+0xa2/0xd0
ip_rcv_finish_core+0x829/0x1950
ip_rcv+0x2d7/0x420
__netif_receive_skb_one_core+0x185/0x1f0
netif_receive_skb+0x90/0x450
tun_get_user+0x3413/0x3fb0
tun_chr_write_iter+0xe4/0x220
...
Fix this by checking rt2->rt_type after ip_route_input(). If it's
RTN_LOCAL, the route cannot be used for output, so treat it as an error.
The reproducer requires kernel modification to widen the race window,
making it unsuitable as a selftest. It is available at:
https://gist.github.com/mrpre/eae853b72ac6a750f5d45d64ddac1e81
CVSS Score
4.7
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix workqueue list corruption by removing work_list
The commit e1168f0 ("RDMA/iwcm: Simplify cm_event_handler()")
changed the work submission logic to unconditionally call
queue_work() with the expectation that queue_work() would
have no effect if work was already pending. The problem is
that a free list of struct iwcm_work is used (for which
struct work_struct is embedded), so each call to queue_work()
is basically unique and therefore does indeed queue the work.
This causes a problem in the work handler which walks the work_list
until it's empty to process entries. This means that a single
run of the work handler could process item N+1 and release it
back to the free list while the actual workqueue entry is still
queued. It could then get reused (INIT_WORK...) and lead to
list corruption in the workqueue logic.
Fix this by just removing the work_list. The workqueue already
does this for us.
This fixes the following error that was observed when stress
testing with ucmatose on an Intel E830 in iWARP mode:
[ 151.465780] list_del corruption. next->prev should be ffff9f0915c69c08, but was ffff9f0a1116be08. (next=ffff9f0a15b11c08)
[ 151.466639] ------------[ cut here ]------------
[ 151.466986] kernel BUG at lib/list_debug.c:67!
[ 151.467349] Oops: invalid opcode: 0000 [#1] SMP NOPTI
[ 151.467753] CPU: 14 UID: 0 PID: 2306 Comm: kworker/u64:18 Not tainted 6.19.0-rc4+ #1 PREEMPT(voluntary)
[ 151.468466] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 151.469192] Workqueue: 0x0 (iw_cm_wq)
[ 151.469478] RIP: 0010:__list_del_entry_valid_or_report+0xf0/0x100
[ 151.469942] Code: c7 58 5f 4c b2 e8 10 50 aa ff 0f 0b 48 89 ef e8 36 57 cb ff 48 8b 55 08 48 89 e9 48 89 de 48 c7 c7 a8 5f 4c b2 e8 f0 4f aa ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90
[ 151.471323] RSP: 0000:ffffb15644e7bd68 EFLAGS: 00010046
[ 151.471712] RAX: 000000000000006d RBX: ffff9f0915c69c08 RCX: 0000000000000027
[ 151.472243] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9f0a37d9c600
[ 151.472768] RBP: ffff9f0a15b11c08 R08: 0000000000000000 R09: c0000000ffff7fff
[ 151.473294] R10: 0000000000000001 R11: ffffb15644e7bba8 R12: ffff9f092339ee68
[ 151.473817] R13: ffff9f0900059c28 R14: ffff9f092339ee78 R15: 0000000000000000
[ 151.474344] FS: 0000000000000000(0000) GS:ffff9f0a847b5000(0000) knlGS:0000000000000000
[ 151.474934] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 151.475362] CR2: 0000559e233a9088 CR3: 000000020296b004 CR4: 0000000000770ef0
[ 151.475895] PKRU: 55555554
[ 151.476118] Call Trace:
[ 151.476331] <TASK>
[ 151.476497] move_linked_works+0x49/0xa0
[ 151.476792] __pwq_activate_work.isra.46+0x2f/0xa0
[ 151.477151] pwq_dec_nr_in_flight+0x1e0/0x2f0
[ 151.477479] process_scheduled_works+0x1c8/0x410
[ 151.477823] worker_thread+0x125/0x260
[ 151.478108] ? __pfx_worker_thread+0x10/0x10
[ 151.478430] kthread+0xfe/0x240
[ 151.478671] ? __pfx_kthread+0x10/0x10
[ 151.478955] ? __pfx_kthread+0x10/0x10
[ 151.479240] ret_from_fork+0x208/0x270
[ 151.479523] ? __pfx_kthread+0x10/0x10
[ 151.479806] ret_from_fork_asm+0x1a/0x30
[ 151.480103] </TASK>
CVSS Score
9.8
EPSS Score
0.006
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
ext4: drop extent cache when splitting extent fails
When the split extent fails, we might leave some extents still being
processed and return an error directly, which will result in stale
extent entries remaining in the extent status tree. So drop all of the
remaining potentially stale extents if the splitting fails.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
xen-netback: reject zero-queue configuration from guest
A malicious or buggy Xen guest can write "0" to the xenbus key
"multi-queue-num-queues". The connect() function in the backend only
validates the upper bound (requested_num_queues > xenvif_max_queues)
but not zero, allowing requested_num_queues=0 to reach
vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers
WARN_ON_ONCE(!size) in __vmalloc_node_range().
On systems with panic_on_warn=1, this allows a guest-to-host denial
of service.
The Xen network interface specification requires
the queue count to be "greater than zero".
Add a zero check to match the validation already present
in xen-blkback, which has included this
guard since its multi-queue support was added.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
net: hns3: fix double free issue for tx spare buffer
In hns3_set_ringparam(), a temporary copy (tmp_rings) of the ring structure
is created for rollback. However, the tx_spare pointer in the original
ring handle is incorrectly left pointing to the old backup memory.
Later, if memory allocation fails in hns3_init_all_ring() during the setup,
the error path attempts to free all newly allocated rings. Since tx_spare
contains a stale (non-NULL) pointer from the backup, it is mistaken for
a newly allocated buffer and is erroneously freed, leading to a double-free
of the backup memory.
The root cause is that the tx_spare field was not cleared after its value
was saved in tmp_rings, leaving a dangling pointer.
Fix this by setting tx_spare to NULL in the original ring structure
when the creation of the new `tx_spare` fails. This ensures the
error cleanup path only frees genuinely newly allocated buffers.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
ext4: drop extent cache after doing PARTIAL_VALID1 zeroout
When splitting an unwritten extent in the middle and converting it to
initialized in ext4_split_extent() with the EXT4_EXT_MAY_ZEROOUT and
EXT4_EXT_DATA_VALID2 flags set, it could leave a stale unwritten extent.
Assume we have an unwritten file and buffered write in the middle of it
without dioread_nolock enabled, it will allocate blocks as written
extent.
0 A B N
[UUUUUUUUUUUU] on-disk extent U: unwritten extent
[UUUUUUUUUUUU] extent status tree
[--DDDDDDDD--] D: valid data
|<- ->| ----> this range needs to be initialized
ext4_split_extent() first try to split this extent at B with
EXT4_EXT_DATA_PARTIAL_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but
ext4_split_extent_at() failed to split this extent due to temporary lack
of space. It zeroout B to N and leave the entire extent as unwritten.
0 A B N
[UUUUUUUUUUUU] on-disk extent
[UUUUUUUUUUUU] extent status tree
[--DDDDDDDDZZ] Z: zeroed data
ext4_split_extent() then try to split this extent at A with
EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and
leave an written extent from A to N.
0 A B N
[UUWWWWWWWWWW] on-disk extent W: written extent
[UUUUUUUUUUUU] extent status tree
[--DDDDDDDDZZ]
Finally ext4_map_create_blocks() only insert extent A to B to the extent
status tree, and leave an stale unwritten extent in the status tree.
0 A B N
[UUWWWWWWWWWW] on-disk extent W: written extent
[UUWWWWWWWWUU] extent status tree
[--DDDDDDDDZZ]
Fix this issue by always cached extent status entry after zeroing out
the second part.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
apparmor: Fix & Optimize table creation from possibly unaligned memory
Source blob may come from userspace and might be unaligned.
Try to optize the copying process by avoiding unaligned memory accesses.
- Added Fixes tag
- Added "Fix &" to description as this doesn't just optimize but fixes
a potential unaligned memory access
[jj: remove duplicate word "convert" in comment trigger checkpatch warning]
CVSS Score
7.1
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Clear Present bit before tearing down PASID entry
The Intel VT-d Scalable Mode PASID table entry consists of 512 bits (64
bytes). When tearing down an entry, the current implementation zeros the
entire 64-byte structure immediately using multiple 64-bit writes.
Since the IOMMU hardware may fetch these 64 bytes using multiple
internal transactions (e.g., four 128-bit bursts), updating or zeroing
the entire entry while it is active (P=1) risks a "torn" read. If a
hardware fetch occurs simultaneously with the CPU zeroing the entry, the
hardware could observe an inconsistent state, leading to unpredictable
behavior or spurious faults.
Follow the "Guidance to Software for Invalidations" in the VT-d spec
(Section 6.5.3.3) by implementing the recommended ownership handshake:
1. Clear only the 'Present' (P) bit of the PASID entry.
2. Use a dma_wmb() to ensure the cleared bit is visible to hardware
before proceeding.
3. Execute the required invalidation sequence (PASID cache, IOTLB, and
Device-TLB flush) to ensure the hardware has released all cached
references.
4. Only after the flushes are complete, zero out the remaining fields
of the PASID entry.
Also, add a dma_wmb() in pasid_set_present() to ensure that all other
fields of the PASID entry are visible to the hardware before the Present
bit is set.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
quota: fix livelock between quotactl and freeze_super
When a filesystem is frozen, quotactl_block() enters a retry loop
waiting for the filesystem to thaw. It acquires s_umount, checks the
freeze state, drops s_umount and uses sb_start_write() - sb_end_write()
pair to wait for the unfreeze.
However, this retry loop can trigger a livelock issue, specifically on
kernels with preemption disabled.
The mechanism is as follows:
1. freeze_super() sets SB_FREEZE_WRITE and calls sb_wait_write().
2. sb_wait_write() calls percpu_down_write(), which initiates
synchronize_rcu().
3. Simultaneously, quotactl_block() spins in its retry loop, immediately
executing the sb_start_write() - sb_end_write() pair.
4. Because the kernel is non-preemptible and the loop contains no
scheduling points, quotactl_block() never yields the CPU. This
prevents that CPU from reaching an RCU quiescent state.
5. synchronize_rcu() in the freezer thread waits indefinitely for the
quotactl_block() CPU to report a quiescent state.
6. quotactl_block() spins indefinitely waiting for the freezer to
advance, which it cannot do as it is blocked on the RCU sync.
This results in a hang of the freezer process and 100% CPU usage by the
quota process.
While this can occur intermittently on multi-core systems, it is
reliably reproducing on a node with the following script, running both
the freezer and the quota toggle on the same CPU:
# mkfs.ext4 -O quota /dev/sda 2g && mkdir a_mount
# mount /dev/sda -o quota,usrquota,grpquota a_mount
# taskset -c 3 bash -c "while true; do xfs_freeze -f a_mount; \
xfs_freeze -u a_mount; done" &
# taskset -c 3 bash -c "while true; do quotaon a_mount; \
quotaoff a_mount; done" &
Adding cond_resched() to the retry loop fixes the issue. It acts as an
RCU quiescent state, allowing synchronize_rcu() in percpu_down_write()
to complete.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-05-27
In the Linux kernel, the following vulnerability has been resolved:
mtd: intel-dg: Fix accessing regions before setting nregions
The regions array is counted by nregions, but it's set only after
accessing it:
[] UBSAN: array-index-out-of-bounds in drivers/mtd/devices/mtd_intel_dg.c:750:15
[] index 0 is out of range for type '<unknown> [*]'
Fix it by also fixing an undesired behavior: the loop silently ignores
ENOMEM and continues setting the other entries.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-05-27