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Echo: linux: security update to 6.12.12-1

high Tenable Self-Hosted Container Security Plugin ID 461955

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize
 freeing resources during CPU hotunplug In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx
 of the current CPU at the beginning of the operation is retrieved and used throughout. However, since
 neither preemption nor migration are disabled, it is possible that the operation continues on a different
 CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as
 some of the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
 acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp). The problem was introduced in commit 1ec3b5fe6eec
 ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when the switch to the crypto_acomp
 API was made. Prior to that, the per-CPU crypto_comp was retrieved using get_cpu_ptr() which disables
 preemption and makes sure the CPU cannot go away from under us. Preemption cannot be disabled with the
 crypto_acomp API as a sleepable context is needed. Use the acomp_ctx.mutex to synchronize CPU hotplug
 callbacks allocating and freeing resources with compression/decompression paths. Make sure that
 acomp_ctx.req is NULL when the resources are freed. In the compression/decompression paths, check if
 acomp_ctx.req is NULL after acquiring the mutex (meaning the CPU was offlined) and retry on the new CPU.
 The initialization of acomp_ctx.mutex is moved from the CPU hotplug callback to the pool initialization
 where it belongs (where the mutex is allocated). In addition to adding clarity, this makes sure that CPU
 hotplug cannot reinitialize a mutex that is already locked by compression/decompression. Previously a fix
 was attempted by holding cpus_read_lock() [1]. This would have caused a potential deadlock as it is
 possible for code already holding the lock to fall into reclaim and enter zswap (causing a deadlock). A
 fix was also attempted using SRCU for synchronization, but Johannes pointed out that synchronize_srcu()
 cannot be used in CPU hotplug notifiers [2]. Alternative fixes that were considered/attempted and could
 have worked: - Refcounting the per-CPU acomp_ctx. This involves complexity in handling the race between
 the refcount dropping to zero in zswap_[de]compress() and the refcount being re-initialized when the CPU
 is onlined. - Disabling migration before getting the per-CPU acomp_ctx [3], but that's discouraged and is
 a much bigger hammer than needed, and could result in subtle performance issues.
 [1]https://lkml.kernel.org/[email protected]/
 [2]https://lkml.kernel.org/[email protected]/
 [3]https://lkml.kernel.org/[email protected]/ [[email protected]: remove
 comment] (CVE-2025-21693)

Solution

Update the linux library and its related packages to version 6.12.12-1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2025-21693

Plugin Details

Severity: High

ID: 461955

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.12

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2025-21693

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 9/15/2025

Vulnerability Publication Date: 2/10/2025

Reference Information

CVE: CVE-2025-21693