Use After Free The advisory has been revoked - it doesn't affect any version of package kernel-rt-kvm  (opens in a new tab)


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  • Snyk IDSNYK-CENTOS8-KERNELRTKVM-7104424
  • published24 May 2024
  • disclosed21 May 2024

Introduced: 21 May 2024

CVE-2021-47281  (opens in a new tab)
CWE-416  (opens in a new tab)

Amendment

The Centos security team deemed this advisory irrelevant for Centos:8.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-kvm package and not the kernel-rt-kvm package as distributed by Centos.

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

ALSA: seq: Fix race of snd_seq_timer_open()

The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently.

For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.