SB2026040697 - NULL pointer dereference in Linux kernel x86 events

Description

This security bulletin contains information about 1 vulnerability.

1) NULL pointer dereference (CVE-ID: CVE-2026-23435)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 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/E:U/U:Clear

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a null pointer dereference in the x86 PMU NMI handler and x86 perf event scheduling logic when unthrottling perf events after rescheduling. A local user can trigger a race condition in perf event handling to cause a denial of service.

The issue occurs because the active counter mask can indicate an active event while the corresponding events[] entry remains NULL, leading to a kernel crash when a PMC overflow NMI handler dereferences the missing event pointer.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/886fa869153917d902784098922defa20c3a2fe5
• https://git.kernel.org/stable/c/8d5fae6011260de209aaf231120e8146b14bc8e0
• https://git.kernel.org/stable/c/c1dd1e2b722d3f1f2e4977dad8d1be78fdfb30cb