SB20260812101 - Use-after-free in Linux kernel kvm mmu



SB20260812101 - Use-after-free in Linux kernel kvm mmu

Published: August 12, 2026

Security Bulletin ID SB20260812101
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-2026-68428)

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 KVM x86 MMU cache cleanup logic when reloading a vendor module after a prior unload. A local user can trigger a vendor module reload sequence with a failed cache initialization to cause a denial of service.

The issue occurs when kvm.ko remains loaded while a vendor module is unloaded and then reloaded, leaving a stale cache pointer that is later passed to kmem_cache_destroy().


Remediation

Install update from vendor's website.