What is CVE-2020-21066?

CVE-2020-21066 is a medium-severity vulnerability in Axiosys Bento4, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2021-08-13.

How severe is CVE-2020-21066?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Buffer overflow in Axiosys Bento4

CVE-2020-21066

An issue was discovered in Bento4 v1.5.1.0. There is a heap-buffer-overflow in AP4_Dec3Atom::AP4_Dec3Atom at Ap4Dec3Atom.cpp, leading to a denial of service (program crash), as demonstrated by mp42aac.

Vulnerability class: Buffer Overflow

Published 2021-08-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.008 (56.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Axiosys Bento4 — versions 1.5.1.0

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

github.com/axiomatic-systems/Bento4/issues/408 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2020-21066?: CVE-2020-21066 is a medium-severity vulnerability in Axiosys Bento4, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2021-08-13.
How severe is CVE-2020-21066?: Medium severity. CVSS v3 base score is 6.5 out of 10.