Description
In FFmpeg 3.2 and 4.1, a denial of service in the subtitle decoder allows attackers to hog the CPU via a crafted video file in Matroska format, because ff_htmlmarkup_to_ass in libavcodec/htmlsubtitles.c has a complex format argument to sscanf.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | ffmpeg | 7:4.1.3-1 | — |
| Debian 13 | ffmpeg | 7:4.1.3-1 | — |
| Debian 12 | ffmpeg | 7:4.1.3-1 | — |
| Debian 9 | ffmpeg | 7:3.2.14-1~deb9u1 | DSA-4449-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | ffmpeg | 7:3.4.6-0ubuntu0.18.04.1 | USN-3967-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | ffmpeg | 3.4.2-4.27.1 | SUSE-SU-2019:3184-2, SUSE-SU-2019:3184-1 |
| SLES 15 | ffmpeg | 3.4.2-4.27.1 | SUSE-SU-2019:3184-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.23 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.22 | ffmpeg +1 | 4.1.3-r0 | — |
| Alpine v3.21 | ffmpeg +1 | 4.1.3-r0 | — |
| Alpine v3.20 | ffmpeg +1 | 4.1.3-r0 | — |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | ffmpeg +1 | 4.1.3-r0 | — |
| Alpine v3.18 | ffmpeg +1 | 4.1.3-r0 | — |
| Alpine v3.17 | ffmpeg +1 | 4.1.3-r0 | — |
| Alpine v3.16 | ffmpeg +1 | 4.1.3-r0 | — |
| Alpine v3.15 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.14 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.13 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.12 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.11 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.10 | ffmpeg | 4.1.3-r0 | — |
| Alpine v3.9 | ffmpeg | 4.0.4-r0 | — |
| Alpine v3.8 | ffmpeg | 3.4.6-r0 | — |
Advisories 4
- USN-3967-1 FFmpeg vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4449-1 ffmpeg - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2019:3184-1 Security update for ffmpeg SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:3184-2 Security update for ffmpeg SUSE / openSUSE Security Updates · May 2, 2025
References
- https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/1f00c97bc3475c477f3c468cf2d924d5761d0982
- 107382 vdb-entry
- USN-3967-1 vendor-advisory
- 20190523 [SECURITY] [DSA 4449-1] ffmpeg security update mailing-list
- DSA-4449 vendor-advisory
- https://github.com/FFmpeg/FFmpeg/commit/23ccf3cabb4baf6e8af4b1af3fcc59c904736f21