CVE-2026-108538 GPAC MP4Box os_thread.c gf_mx_v use after free
A use-after-free vulnerability in GPAC's MP4Box allows remote attackers to potentially execute code or cause denial of service via crafted media files.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-108538?
CVE-2026-108538 is a medium-severity use after free vulnerability in GPAC, published on 11 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A security vulnerability has been detected in GPAC up to 26.07.0. The impacted element is the function gf_mx_v of the file utils/os_thread.c of the component MP4Box. Such manipulation leads to use after free. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Which versions are affected by CVE-2026-108538?
How do I fix CVE-2026-108538?
No fix has been published for CVE-2026-108538 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-108538 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-108538 exists.
Sources
Also known as GHSA-6qp9-3j3r-w3r5, UBUNTU-CVE-2026-108538.