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.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-099762 advisory.

    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.

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-100746 advisory.

    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.

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

An update of the linux package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-53265)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
341024	SUSE SLED15: cluster-md-kmp-default / dlm-kmp-default / gfs2-kmp-default / etc (SUSE-SU-2026:3790-1)	Nessus	SuSE Local Security Checks	Local	high
336754	Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099762)	Nessus	Unity Linux Local Security Checks	Local	high
336159	Unity Linux 20.1050a Security Update: kernel (UTSA-2026-100746)	Nessus	Unity Linux Local Security Checks	Local	high
335080	openSUSE 16: cluster-md-kmp-64kb / cluster-md-kmp-azure / cluster-md-kmp-default / etc (openSUSE-SU-2026:21555-1)	Nessus	SuSE Local Security Checks	Local	high
332499	Photon OS 5.0: Linux PHSA-2026-5.0-92-0928	Nessus	PhotonOS Local Security Checks	Local	high
329325	Photon OS 5.0: Linux PHSA-2026-5.0-0928	Nessus	PhotonOS Local Security Checks	Local	high
327383	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1925)	Nessus	Amazon Linux Local Security Checks	Local	high
323588	Linux Distros Unpatched Vulnerability : CVE-2026-53265	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-53265

high

Tenable Plugins

high

high

high

high

high

high

high

high