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.
History

Sat, 15 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-824
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 14 Aug 2026 17:15:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*

Sat, 08 Aug 2026 03:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 07 Aug 2026 17:30:00 +0000


Fri, 07 Aug 2026 02:15:00 +0000

Type Values Removed Values Added
First Time appeared Ffmpeg
Ffmpeg ffmpeg
Vendors & Products Ffmpeg
Ffmpeg ffmpeg

Thu, 06 Aug 2026 22:15:00 +0000

Type Values Removed Values Added
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.
Title FFmpeg 0.5 < 9.0 Uninitialized Heap Memory Read in TIFF Decoder
Weaknesses CWE-908
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 6.8, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-08-06T21:25:53.036Z

Updated: 2026-08-14T16:51:33.474Z

Reserved: 2026-08-04T20:17:18.297Z

Link: CVE-2026-70631

cve-icon Vulnrichment

Updated: 2026-08-08T02:44:13.411Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-06T22:18:27.420

Modified: 2026-09-01T15:33:18.453

Link: CVE-2026-70631

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-06T21:25:53Z

Links: CVE-2026-70631 - Bugzilla