CVE-2026-66038
Publication date 24 July 2026
Last updated 25 August 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| ffmpeg | 26.04 LTS resolute |
Vulnerable
|
| 24.04 LTS noble |
Fixed 7:6.1.1-3ubuntu5+esm11
|
|
| 22.04 LTS jammy |
Fixed 7:4.4.2-0ubuntu0.22.04.1+esm13
|
|
| 20.04 LTS focal |
Fixed 7:4.2.7-0ubuntu0.1+esm14
|
|
| 18.04 LTS bionic |
Fixed 7:3.4.11-0ubuntu0.1+esm13
|
|
| 16.04 LTS xenial |
Fixed 7:2.8.17-0ubuntu0.1+esm15
|
|
| libav | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 14.04 LTS trusty |
Needs evaluation
|
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CVSS version:
Base score
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
Base score
6.5 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8671-1
- FFmpeg vulnerabilities
- 24 August 2026