What is CVE-2018-6621?

CVE-2018-6621 is a medium-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2018-02-05.

How severe is CVE-2018-6621?

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

Out-of-bounds Read in Ffmpeg

CVE-2018-6621

The decode_frame function in libavcodec/utvideodec.c in FFmpeg through 3.2 allows remote attackers to cause a denial of service (out of array read) via a crafted AVI file.

Vulnerability class: Buffer Overflow

Published 2018-02-05 · 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: 0.022 (81.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 81.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.022 · newest: 0.022 · change: 0.000

Affected products

Ffmpeg
Debian Linux — versions 8.0, 9.0

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

www.securityfocus.com/bid/102950 (VDB Entry, Third Party Advisory, vdb-entry)
git.ffmpeg.org/gitweb/ffmpeg.git/commit/118e1b0b3370dd1c0da442901b486689efd1654b (Patch, Third Party Advisory)
www.debian.org/security/2018/dsa-4249 (vendor-advisory, Third Party Advisory)
lists.debian.org/debian-lts-announce/2019/01/msg00006.html (mailing-list, Mailing List, Third Party Advisory)
github.com/FFmpeg/FFmpeg/commit/22aa37c0fedf14531783189a197542a055959b6c (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2018-6621?: CVE-2018-6621 is a medium-severity vulnerability in Ffmpeg, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2018-02-05.
How severe is CVE-2018-6621?: Medium severity. CVSS v3 base score is 6.5 out of 10.