CVE-2026-70631

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 v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/2f234ea34c81288e3840fca632dd16481d8de39f	Patch
https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/3c287af3affe1286350faa69c02bcc5d49de18bb	Patch
https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/a991b1fecbd8c9e6f4fc31c191bd12e4be27dbf7	Patch
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23899	Issue Tracking Patch
https://www.vulncheck.com/advisories/ffmpeg-uninitialized-heap-memory-read-in-tiff-decoder	Patch Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-08-06 22:18

Updated : 2026-09-01 15:33

NVD link : CVE-2026-70631

Mitre link : CVE-2026-70631

CVE.ORG link : CVE-2026-70631

JSON object : View

Products Affected

ffmpeg

ffmpeg

CWE

CWE-908

Use of Uninitialized Resource

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