Bug 2512210 (CVE-2026-70631)

Summary: CVE-2026-70631 FFmpeg: FFmpeg: Information disclosure via uninitialized heap memory read in TIFF decoder
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bbrownin
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in FFmpeg. An attacker can exploit an uninitialized heap memory disclosure vulnerability in the native TIFF decoder by providing a specially crafted TIFF file. This crafted file can cause the `tiff_unpack_zlib()` function to include stale data from previous memory allocations in the decoded image output. This could potentially expose sensitive information in persistent services.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2516040, 2516041, 2516042, 2516043, 2516047    
Bug Blocks:    

Description OSIDB Bzimport 2026-08-06 22:22:21 UTC 
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.