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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-66038 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  VulnCheck
CVSS-B 7.1 HIGH
Vector:  CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/e7cbfd1c507b57a806a5825b87d609963e862c8c VulnCheck
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23626 VulnCheck
https://www.vulncheck.com/advisories/ffmpeg-lcl-zlib-video-decoder-information-disclosure-via-lcldec-c VulnCheck

Weakness Enumeration

CWE-ID CWE Name Source
CWE-908 Use of Uninitialized Resource VulnCheck  

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-66038
NVD Published Date:
07/24/2026
NVD Last Modified:
07/24/2026
Source:
VulnCheck