PatchTheCVECVE-2026-66038: FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the LCL/ZLI
CVE-2026-66038 is a medium-severity flaw (CVSS 6.5) affecting ffmpeg. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.2% (top 85%) |
| CISA exploited list | No |
| Weakness | CWE-908 |
| Published | 2026-07-24 |
| Last modified | 2026-08-07 |
Last updated 2026-08-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-66038?
ffmpeg: upgrade to newer than 8.1.2. Exact commands for each OS are on this page.
Is CVE-2026-66038 being exploited?
CVE-2026-66038 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-66038 affect?
CVE-2026-66038 affects ffmpeg. Severity is medium (CVSS 6.5). 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
How urgent is CVE-2026-66038?
Priority 27/100. No elevated risk signals yet.
Software pages
zlib vulnerabilities · FFmpeg vulnerabilities
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