CVE-2026-27821 GPAC NHML Demuxer (dmx_nhml.c) Vulnerable to Stack Buffer Overflow
A stack buffer overflow in GPAC's NHML demuxer allows attackers to execute arbitrary code or cause denial of service via crafted files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-27821?
CVE-2026-27821 is a high-severity memory corruption vulnerability in Gpac Gpac, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
GPAC is an open-source multimedia framework. In versions up to and including 26.02.0, a stack buffer overflow occurs during NHML file parsing in `src/filters/dmx_nhml.c`. The value of the xmlHeaderEnd XML attribute is copied from att->value into szXmlHeaderEnd[1000] using strcpy() without any length validation. If the input exceeds 1000 bytes, it overwrites beyond the stack buffer boundary. Commit 9bd7137fded2db40de61a2cf3045812c8741ec52 patches the issue.
Weakness: CWE-121
Which versions are affected by CVE-2026-27821?
It affects 1 product.
Products include Gpac Gpac.
How do I fix CVE-2026-27821?
No fix has been published for CVE-2026-27821 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-27821 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27821 exists.
Other vulnerabilities in Gpac Gpac
Sources
Also known as DEBIAN-CVE-2026-27821, GHSA-q7qh-8r2r-q559, UBUNTU-CVE-2026-27821.