CVE-2026-70631

Name	CVE-2026-70631
Description	FFmpeg versions from 0.5 up to, but not including, 9.0 contain an uninitialized heap memory disclosure vulnerability in the native TIFF decoder in libavcodec/tiff.c. An attacker who can cause FFmpeg to decode a crafted TIFF file can supply a valid Deflate-compressed strip that terminates successfully after producing fewer bytes than the declared strip requires. The tiff_unpack_zlib() function allocates a heap buffer sized for the full declared strip but copies all declared rows via memcpy() regardless of how many bytes zlib actually decompressed, causing unwritten bytes that can contain stale data from prior heap allocations to be incorporated into decoded image output and potentially exposing sensitive data in persistent services.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
ffmpeg (PTS)	bullseye	7:4.3.7-0+deb11u1	vulnerable
	bullseye (security)	7:4.3.9-0+deb11u2	vulnerable
	bookworm, bookworm (security)	7:5.1.9-0+deb12u1	vulnerable
	trixie (security), trixie	7:7.1.5-0+deb13u1	vulnerable
	forky, sid	7:8.1.2-2	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
ffmpeg	source	(unstable)	(unfixed)

Notes

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23899
Introduced with: https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/a991b1fecbd8c9e6f4fc31c191bd12e4be27dbf7 ((v0.5)
Fixed by: https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/2f234ea34c81288e3840fca632dd16481d8de39f (master)
Fixed by: https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/3c287af3affe1286350faa69c02bcc5d49de18bb (n9.0)