What is CVE-2021-21861?

CVE-2021-21861 is a high-severity vulnerability in Gpac, classified under Integer Overflow to Buffer Overflow. CVSS score: 8.8/10. Published 2021-08-16.

How severe is CVE-2021-21861?

High severity. CVSS v3 base score is 8.8 out of 10.

Vulnerability in Gpac

CVE-2021-21861

An exploitable integer truncation vulnerability exists within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. When processing the 'hdlr' FOURCC code, a specially crafted MPEG-4 input can cause an improper memory allocation resulting in a heap-based buffer overflow that causes memory corruption. An attacker can convince a user to open a video to trigger this vulnerability.

Published 2021-08-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.016 (75.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

Gpac — versions 1.0.1
Debian Linux — versions 11.0
Gpac Project — versions GPAC Project Advanced Content commit a8a8d412dabcb129e695c3e7d861fcc81f608304, GPAC Project Advanced Content v1.0.1

Weakness classification (CWE)

References

talosintelligence.com/vulnerability_reports/TALOS-2021-1298 (Exploit, Third Party Advisory)
www.debian.org/security/2021/dsa-4966 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21861?: CVE-2021-21861 is a high-severity vulnerability in Gpac, classified under Integer Overflow to Buffer Overflow. CVSS score: 8.8/10. Published 2021-08-16.
How severe is CVE-2021-21861?: High severity. CVSS v3 base score is 8.8 out of 10.