SB20260824257 - Use-after-free in Linux kernel sched
Published: August 24, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-74583)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in the route4 fastmap cache in the cls_route classifier when classifying packets concurrently with filter deletion or modification. A local user can trigger concurrent packet classification and filter updates to cause a denial of service.
The issue is caused by a race in which an in-flight reader can republish a stale filter pointer into the fastmap after the entry has been reset and before the deferred free completes.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/stable/c/0e7a8cf8895b06d07c7311f028eba16ad742b9bc
- https://git.kernel.org/stable/c/47d7f7051253bdc02b1d245d87e38f16d31a74df
- https://git.kernel.org/stable/c/5ec9001be6d0eb527251125632ec8fe88278897f
- https://git.kernel.org/stable/c/7897198b26445b4009a057bda1986b94a99e5d5f
- https://git.kernel.org/stable/c/820f083c294ad6d319c02a7d43294f2ed2565139
- https://git.kernel.org/stable/c/a17f636c9330eac879822ce29f998e5abd1b72c1
- https://git.kernel.org/stable/c/ae9aff87025219005a2d16b4fe83d6f24643e50d
- https://git.kernel.org/stable/c/b969984b2bdc85d721ce4047cd270cd37ec705a2