Time-of-check Time-of-use (TOCTOU) Affecting kernel package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-RHEL7-KERNEL-21611844
- published23 Oct 2026
- disclosed16 Sept 2026
Introduced: 16 Sep 2026
CVE-2026-89979 (opens in a new tab)How to fix?
There is no fixed version for RHEL:7 kernel.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by RHEL.
See How to fix? for RHEL:7 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix race between non-atomic ops and trigger-start
We protect the races of the concurrent state transitions between atomic PCM ops, but the checks between the non-atomic ops (hw_params, hw_free and prepare) and the atomic ops aren't perfect; there is a check of the conflicting PCM state at the beginning of hw_params & co, but the atomic PCM ops can be still issued during the non-atomic PCM operations. An example such scenario is that a thread A re-issues the PREPARE or HW_PARAMS for the already prepared stream, while another thread B triggers the PCM start in the middle of the prepare operation. Although this usually doesn't lead to much serious issues, it can give some inconsistency as reported by syzkaller (such as ODEBUG warning).
There are various atomic PCM ops, and basically the only problem is the PCM start as it operates from the PREPARED state. Other trigger commands (stop, etc) are for the running or the other special state, hence they are filtered as pre-condition.
This patch is for preventing the PCM trigger-start during the non- atomic operations in order to address the problems above. Fortunately, the hw_params, hw_free and prepare operations call snd_pcm_buffer_access_lock(), and this can be used for checking the concurrent operations at the PCM trigger -- which sets the runtime->buffer_accessing to a negative (if possible), so the PCM trigger just needs to check the runtime->buffer_accessing value; if it's negative, it means the concurrent non-atomic PCM ops is running.
References
- https://access.redhat.com/security/cve/CVE-2026-89979
- https://git.kernel.org/stable/c/50afadf1ea66597116eb14e73c24da7ae99b759f
- https://git.kernel.org/stable/c/5abeb4f9f2023f001d693b4e5e1ebbf25e25d0eb
- https://git.kernel.org/stable/c/7ad2ea7c10044b08ecf7b04376916faf12e17a99
- https://git.kernel.org/stable/c/acac7b5e07349a9d10d78873afb4b93cd1dc721f
- https://git.kernel.org/stable/c/ad29779736cfd6f5595f0cab300dd7611418e363
- https://git.kernel.org/stable/c/b1d12144557fceed5de6e22e2c2e30a40ed37702
- https://git.kernel.org/stable/c/b2edc017f94c08bdd0b046a586e43ac771a2f942
- https://git.kernel.org/stable/c/b599e7f16441386754ec083fa62a549bccb02fca