CVE-2026-125233

CVSS 8.5 (high) · published 2026-11-09

FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in dvbsub_encode() in libavcodec/dvbsubenc.c that undercounts each CLUT segment header by two bytes. Attackers can supply a file with many bitmap subtitle rectangles that, when transcoded to the dvbsub encoder, writes past the output buffer and corrupts heap memory.

Weakness: CWE-131

Source: NVD CVE-2026-125233

References

• https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24913
• https://github.com/FFmpeg/FFmpeg
• https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/dvbsubenc.c#L363
• https://github.com/FFmpeg/FFmpeg/commit/7f80b2ad83f37a4998d9617495c92b28a7339a90
• https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-dvb-subtitle-encoder

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