---
id: "CVE-2026-125195"
page: "https://infrastack.ai/live/CVE-2026-125195"
kind: "vulnerability"
aliases: ["CVE-2026-125195"]
title: "FFmpeg: uninitialized heap memory leaks into ADPCM_MS encoded audio output"
severity: "low"
cvss: 2.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["audio-transcoding", "ffmpeg", "libavcodec", "package"]
not_affected_if: ["no-adpcm-ms-encoding", "no-user-submitted-audio"]
published_at: "2026-11-09T19:16:55+00:00"
first_seen_at: "2026-11-09T19:28:17+00:00"
updated_at: "2026-11-09T19:33:44+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125195", "first_seen_at": "2026-11-09T19:28:17+00:00"}]
exploit_sources: []
---

# FFmpeg: uninitialized heap memory leaks into ADPCM_MS encoded audio output

Link for people: https://infrastack.ai/live/CVE-2026-125195 (this .md is for agents)

FFmpeg through 9.0.2 has an uninitialized memory bug in the ADPCM encoder that leaks heap bytes when encoding mono ADPCM_MS audio with trellis enabled. An attacker who submits audio to a service that encodes this way can read stale heap memory from the encoded output.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed FFmpeg version with `ffmpeg -version`; versions through `9.0.2` are described as affected.
- Look for services that encode audio with `-c:a adpcm_ms` and trellis enabled, such as user-uploaded audio transcoding pipelines.

## Timeline

- 2026-11-09T19:28:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125195

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-uninitialized-memory-disclosure-via-adpcm-ms-trellis-encoding
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/fb13409aaffc151f602ad357db46052e98ea46e8

## From the sources

FFmpeg through 9.0.2 contains an uninitialized memory disclosure vulnerability in adpcm_encode_frame() in libavcodec/adpcmenc.c that leaks heap bytes when encoding mono ADPCM_MS audio with trellis enabled. Attackers submitting audio to a service using this encoding receive output packets where about half of each block contains stale heap memory from the encoding process.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_