FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap buffer overflow vulnerability in the DVD subtitle encoder that underestimates RLE…
CVE-2026-125209
FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap buffer overflow vulnerability in the DVD subtitle encoder that underestimates RLE output size for odd-width rectangles. Attackers can supply files with crafted bitmap subtitles that, when transcoded to the dvdsub encoder, write past the output buffer and corrupt heap memory.
Assessment
- CVSS
- 8.5 (v4.0)
- Severity
- High
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 9 November 2026
- Last updated
- 9 November 2026
- Assigner
- VulnCheck
CVSS vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
At the source
References
- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24486
- https://github.com/FFmpeg/FFmpeg/commit/8702f12c9daa199cc4d7c17164b13c3cdcdc2436
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/dvdsubenc.c#L344
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-buffer-overflow-via-dvdsubenc-c
- https://nvd.nist.gov/vuln/detail/CVE-2026-125209
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