CVE-2026-53265

HIGHCVSS 7.8/10EPSS 0.13%

Last modified

CVE-2026-53265 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: dm cache policy smq: check allocation under invalidate lock commit 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section. That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. EPSS estimates a 0.13% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: dm cache policy smq: check allocation under invalidate lock commit 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section. That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. The first invalidator that acquires the lock removes the entry from the queues and hash table and then calls free_entry(), which clears e->allocated and puts the entry back on the free list. The second invalidator can then acquire mq->lock and continue with the stale result of the unlocked check. This can corrupt the SMQ queues or hash table by deleting an entry that is no longer on those structures. It can also hit the allocation check in free_entry() when the same entry is freed again. Move the allocation check under mq->lock so the predicate and the destructive operations are serialized by the same lock.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.13%

2.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 6.6.141, < 6.6.143
LinuxLinux Kernel>= 6.12.91, < 6.12.94
LinuxLinux Kernel>= 6.18.33, < 6.18.36
LinuxLinux Kernel>= 7.0.10, < 7.0.13
LinuxLinux Kernel5.10.258
LinuxLinux Kernel5.15.209
LinuxLinux Kernel6.1.175
LinuxLinux Kernel7.1Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-53265?
In the Linux kernel, the following vulnerability has been resolved: dm cache policy smq: check allocation under invalidate lock commit 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section. That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. The first invalidator that acquires the lock removes the entry from the queues and hash table and then calls free_entry(), which clears e->allocated and puts the entry back on the free list. The second invalidator can then acquire mq->lock and continue with the stale result of the unlocked check. This can corrupt the SMQ queues or hash table by deleting an entry that is no longer on those structures. It can also hit the allocation check in free_entry() when the same entry is freed again. Move the allocation check under mq->lock so the predicate and the destructive operations are serialized by the same lock.
How severe is CVE-2026-53265?
CVE-2026-53265 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.
How do I fix CVE-2026-53265?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST