CVE-2026-66038

Name	CVE-2026-66038
Description	FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the LCL/ZLIB video decoder that allows attackers to expose uninitialized heap memory by supplying a valid zlib stream that inflates to fewer bytes than the expected frame size. The zlib_decomp() function in lcldec.c treats short decompression as non-fatal and continues to the RGB24 conversion path, which copies a full frame's worth of rows from the allocation buffer using original frame dimensions, causing uninitialized heap contents including pointer-derived allocator bytes to be copied into the attacker-observable AVFrame output and potentially defeating ASLR in long-lived media processing 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)	bookworm, bookworm (security)	7:5.1.9-0+deb12u1	vulnerable
	trixie (security), trixie	7:7.1.5-0+deb13u1	vulnerable
	forky	7:8.1.2-2	vulnerable
	sid	7:9.0.2-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
ffmpeg	source	(unstable)	7:9.0.2-1

Notes

[trixie] - ffmpeg <postponed> (Wait until fixed in 7.1.x upstream branch)
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23626
Fixed by: https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/e7cbfd1c507b57a806a5825b87d609963e862c8c (master)
Fixed by: https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/7c0b8c8594501dd904ebbb3b45bb3f6e2c745b7d (n9.0)