SB20260824257 - Use-after-free in Linux kernel sched



SB20260824257 - Use-after-free in Linux kernel sched

Published: August 24, 2026

Security Bulletin ID SB20260824257
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • 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.