CVE-2026-53265
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk3th percentile — higher than 3% of all known CVEs
Summary
In the Linux kernel, a race condition was found in the SMQ cache policy manager during cache block invalidation. The allocation check (e->allocated) was performed outside the mq->lock critical section, allowing two concurrent invalidators to corrupt data structures.
Risk Assessment
An attacker could exploit this vulnerability to cause a system crash (kernel panic) or potentially escalate privileges by triggering the race condition, threatening system stability and security.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit 2d1f7b65f5de moving the allocation check under mq->lock).
Original NVD description (English source)
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.