Answer in brief
CVE-2026-125103 records a Medium severity (CVSS 4.8) vulnerability in FFmpeg through 9.0.2 Uninitialized Heap Disclosure via MLZ Decompressor in ALS Decoder. The current sources do not mark it as known exploited. The current feed maps FFmpeg/FFmpeg (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 4.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps FFmpeg/FFmpeg (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| FFmpeg/FFmpeggeneric | >=0 <=9.0.2 | Not reported |
Published upstream
Nov 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 9, 2026
FFmpeg through 9.0.2 contains an information disclosure vulnerability in ff_mlz_decompression() in libavcodec/mlz.c, which accepts string codes beyond the dictionary's next free code. Attackers can supply a crafted MPEG-4 ALS file with malformed initial or out-of-range codes to copy uninitialized heap bytes into decoded audio output.
Quoted source text, attributed separately from HOL analysis.