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Fencer Vulns
critical 9.8

CVE-2020-12284 json

`cbs_jpeg_split_fragment` in `libavcodec/cbs_jpeg.c` in FFmpeg 4.1 and 4.2.2 has a heap-based buffer...

published 2020-04-28 6 y ago modified 2026-07-23 3 mo ago also EUVD-2020-4596 , JLSEC-2025-108

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.9%
EPSS 3.9% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

cbs_jpeg_split_fragment in libavcodec/cbs_jpeg.c in FFmpeg 4.1 and 4.2.2 has a heap-based buffer overflow during JPEG_MARKER_SOS handling because of a missing length check.

Patch / fix

  • julia FFMPEG_jll 4.3.1+0
  • ffmpeg Debian 14, Debian 13, Debian 12 7:4.2.3-1

debian advisories DEBIAN-CVE-2020-12284

  • ffmpeg Ubuntu 20.04 LTS 7:4.2.4-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2020-12284

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • ffmpeg Alpine 3.10 4.1.6-r0
  • ffmpeg Alpine 3.11 4.2.4-r0
  • ffmpeg Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 4.3-r0
  • ffmpeg4 Alpine 3.22, Alpine 3.21, Alpine 3.20 +4 more 4.3-r0

alpine advisories ALPINE-CVE-2020-12284

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-12284 updated cvss 9.8

ffmpeg: heap-based buffer overflow during JPEG_MARKER_SOS handling because of a missing length check in libavcodec/cbs_jpeg.c

  • Red Hat Enterprise Linux 5 qffmpeg
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.85% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.chromium.org https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=19734 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia FFMPEG_jll
<4.3.1+0
4.3.1+0

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.