High severity · published Feb 26, 2026
CVE-2026-27821
GPAC NHML Demuxer (dmx_nhml.c) Vulnerable to Stack Buffer Overflow
7.8
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GP
gpac · gpac
<= 26.02.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27821
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27821
Patch
https://github.com/gpac/gpac/commit/9bd7137fded2db40de61a2cf3045812c8741ec52
Exploit
https://github.com/gpac/gpac/security/advisories/GHSA-q7qh-8r2r-q559
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