CVE-2021-21857

Name: CVE-2021-21857
Creator: NVD / NIST
Published: 2021-08-18T13:15:08.047+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.66%

Last modified Jun 17, 2026

CVE-2021-21857 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Multiple exploitable integer overflow vulnerabilities exist within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. A specially crafted MPEG-4 input can cause an integer overflow due to unchecked addition arithmetic resulting in a heap-based buffer overflow that causes memory corruption. EPSS estimates a 1.66% chance of exploitation in the next 30 days.

Description

Multiple exploitable integer overflow vulnerabilities exist within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. A specially crafted MPEG-4 input can cause an integer overflow due to unchecked addition arithmetic 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.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability

1.66%

73.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Gpac	Gpac	1.0.1
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1299Exploit, Technical Description, Third Party Advisory
https://www.debian.org/security/2021/dsa-4966Third Party Advisory
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1299Exploit, Technical Description, Third Party Advisory
https://www.debian.org/security/2021/dsa-4966Third Party Advisory

Timeline

Published: Aug 18, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21857?

How severe is CVE-2021-21857?

CVE-2021-21857 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.66% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21857?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21857?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST