Use of Uninitialized Resource Affecting ffmpeg package, versions <7:4.2.7-0ubuntu0.1+esm14


Severity

Recommended
0.0
medium
0
10

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.24% (16th percentile)

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  • Snyk IDSNYK-UBUNTU2004-FFMPEG-18323446
  • published20 Aug 2026
  • disclosed24 Jul 2026

Introduced: 24 Jul 2026

CVE-2026-66038  (opens in a new tab)
CWE-908  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 ffmpeg to version 7:4.2.7-0ubuntu0.1+esm14 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ffmpeg package and not the ffmpeg package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1