Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/2f234ea34c81288e3840fca632dd16481d8
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/3c287af3affe1286350faa69c02bcc5d49d
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/a991b1fecbd8c9e6f4fc31c191bd12e4be2
- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23899
- https://www.vulncheck.com/advisories/ffmpeg-uninitialized-heap-memory-read-in-ti
FAQ
What is CVE-2026-70631?
CVE-2026-70631 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 t...
How severe is CVE-2026-70631?
CVE-2026-70631 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-70631?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.