What is CVE-2021-33815?

CVE-2021-33815 is a high-severity vulnerability in Ffmpeg, classified under Improper Validation of Array Index. CVSS score: 8.8/10. Published 2021-06-03.

How severe is CVE-2021-33815?

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

Is CVE-2021-33815 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Ffmpeg

CVE-2021-33815

dwa_uncompress in libavcodec/exr.c in FFmpeg 4.4 allows an out-of-bounds array access because dc_count is not strictly checked.

Published 2021-06-03 · 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: 0.014 (70.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 70.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Ffmpeg — versions 4.4

Weakness classification (CWE)

CWE-129 — Improper Validation of Array Index

Public proof-of-concept exploits

References

github.com/FFmpeg/FFmpeg/commit/26d3c81bc5ef2f8c3f09d45eaeacfb4b1139a777 (Patch, Third Party Advisory)
security.gentoo.org/glsa/202312-14 (vendor-advisory)

Frequently asked questions

What is CVE-2021-33815?: CVE-2021-33815 is a high-severity vulnerability in Ffmpeg, classified under Improper Validation of Array Index. CVSS score: 8.8/10. Published 2021-06-03.
How severe is CVE-2021-33815?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2021-33815 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.