---
id: "CVE-2026-125095"
page: "https://infrastack.ai/live/CVE-2026-125095"
kind: "vulnerability"
aliases: ["CVE-2026-125095"]
title: "FFmpeg: crafted C93 video file leaks uninitialized stack memory into frames"
severity: "medium"
cvss: 4.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "libavcodec", "media-processing", "package"]
not_affected_if: ["c93-decoder-unused", "no-untrusted-media"]
published_at: "2026-11-09T19:16:50+00:00"
first_seen_at: "2026-11-09T19:28:15+00:00"
updated_at: "2026-11-09T19:33:40+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125095", "first_seen_at": "2026-11-09T19:28:15+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted C93 video file leaks uninitialized stack memory into frames

Link for people: https://infrastack.ai/live/CVE-2026-125095 (this .md is for agents)

FFmpeg's C93 video decoder in libavcodec never checks how many color table bytes were copied, so a crafted truncated Interplay C93 file makes it write uninitialized stack bytes into decoded frames. An attacker can read stack memory contents through the decoded 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`; the sources cover releases through `9.0.2`.
- Find whether the service decodes untrusted media with FFmpeg, since the flaw needs a crafted Interplay C93 file to be decoded.

## Timeline

- 2026-11-09T19:28:15+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125095

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-c93-decoder-uninitialized-stack-memory-disclosure
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/ac0106851a4dac555c967421dfc96c0135183133

## From the sources

FFmpeg through 9.0.2 contains an uninitialized memory use vulnerability in the C93 video decoder in libavcodec/c93.c, where decode_frame() never checks how many color table bytes were copied. Attackers can supply a crafted truncated Interplay C93 file so draw_n_color() writes uninitialized stack bytes into decoded frames, disclosing stack memory contents.

---

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