CVE-2024-43102: umtx Kernel panic or Use-After-Free

Severity: critical (CVSS 10.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-09-05 · updated 2026-06-17
Weakness: CWE-416

Description

Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of UMTX_OP_SHM can lead to decreasing the reference count of the object representing the mapping too many times, causing it to be freed too early. A malicious code exercizing the UMTX_SHM_DESTROY sub-request in parallel can panic the kernel or enable further Use-After-Free attacks, potentially including code execution or Capsicum sandbox escape.

Affected products

FreeBSD: from 13.0 before 13.3; 13.3, 13.3-p1, 13.3-p2, 13.3-p3, 13.3-p4, 13.3-p5 (+18) — fixed in 13.3

How to fix

Upgrade to a fixed version: FreeBSD 13.3. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2024-43102 or the next vulnerability affects your stack