Expired Pointer Dereference Affecting kernel-rt-doc package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.21% (12th percentile)

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  • Snyk IDSNYK-CENTOS7-KERNELRTDOC-18689199
  • published12 Aug 2026
  • disclosed10 Aug 2026

Introduced: 10 Aug 2026

NewCVE-2026-68202  (opens in a new tab)
CWE-825  (opens in a new tab)

How to fix?

There is no fixed version for Centos:7 kernel-rt-doc.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-doc package and not the kernel-rt-doc package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ALSA: seq: close a re-opened queue timer in the destructor

queue_delete() closes the queue timer, then frees it. snd_seq_timer_close() clears q->timer->timeri. snd_use_lock_sync() then drains borrowers, and snd_seq_timer_delete() frees q->timer.

A borrower can re-open the timer inside that window. A SET_QUEUE_CLIENT that took a queueptr() use_lock reference before the queue was unlinked runs snd_seq_timer_open() after the close. Open refuses re-open only while timeri is set, and the close just cleared it, so it re-opens timeri.

snd_seq_timer_delete() does not close that instance. Its snd_seq_timer_stop() is a no-op, because running was cleared first. So it frees q->timer with the instance still live. The queue is freed next.

The instance stays on the global timer with callback_data pointing at the freed queue. A non-owner START on the unlocked queue arms it. The next tick derefs the freed queue in snd_seq_timer_interrupt().

Reachable by an unprivileged user with access to /dev/snd/seq. No CAP and no queue ownership required.

Close any lingering instance in the destructor. There, ->timeri can no longer change: the queue is unlinked and all use_lock borrowers have drained, so no snd_seq_queue_use() can re-open it. Close it before clearing q->timer. snd_timer_close() waits for any in-flight snd_seq_timer_interrupt() to finish, and that callback still reads q->timer (via snd_seq_check_queue()), so q->timer must stay valid until it drains.

CVSS Base Scores

version 3.1