What is CVE-2020-20902?

CVE-2020-20902 is a medium-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2021-09-20.

How severe is CVE-2020-20902?

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

Out-of-bounds Read in Ffmpeg

CVE-2020-20902

A CWE-125: Out-of-bounds read vulnerability exists in long_term_filter function in g729postfilter.c in FFmpeg 4.2.1 during computation of the denominator of pseudo-normalized correlation R'(0), that could result in disclosure of information.

Vulnerability class: Buffer Overflow

Published 2021-09-20 · 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:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.012 (66.1th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Ffmpeg — versions 4.2.1

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

trac.ffmpeg.org/ticket/8176 (Patch, Issue Tracking, Vendor Advisory)
git.videolan.org/

Frequently asked questions

What is CVE-2020-20902?: CVE-2020-20902 is a medium-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2021-09-20.
How severe is CVE-2020-20902?: Medium severity. CVSS v3 base score is 6.5 out of 10.