Buffer overflow in Gpac
CVE-2026-27821
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (32.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 32.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Gpac — versions <= 26.02.0
Weakness classification (CWE)
References
- github.com/gpac/gpac/security/advisories/GHSA-q7qh-8r2r-q559 (Exploit, Vendor Advisory)
- github.com/gpac/gpac/commit/9bd7137fded2db40de61a2cf3045812c8741ec52 (Patch)
Frequently asked questions
- What is CVE-2026-27821?
- CVE-2026-27821 is a high-severity vulnerability in Gpac, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-02-26.
- How severe is CVE-2026-27821?
- High severity. CVSS v3 base score is 7.8 out of 10.