CVE-2026-27821: GPAC NHML Demuxer (dmx_nhml.c) Vulnerable to Stack Buffer Overflow

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-26 · updated 2026-06-17
Weakness: CWE-121

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.

Affected products

GPAC: through 26.02.0

References

https://github.com/gpac/gpac/commit/9bd7137fded2db40de61a2cf3045812c8741ec52
https://github.com/gpac/gpac/security/advisories/GHSA-q7qh-8r2r-q559
https://github.com/gpac/gpac/security/advisories/GHSA-q7qh-8r2r-q559

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