---
id: "CVE-2026-125172"
page: "https://infrastack.ai/live/CVE-2026-125172"
kind: "vulnerability"
aliases: ["CVE-2026-125172"]
title: "FFmpeg: crafted EVC media file reads past packet buffer"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "media-processing", "package"]
not_affected_if: ["no-evc-decoding", "trusted-media-only"]
published_at: "2026-11-09T19:16:52+00:00"
first_seen_at: "2026-11-09T19:28:16+00:00"
updated_at: "2026-11-09T19:30:19+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125172", "first_seen_at": "2026-11-09T19:28:16+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted EVC media file reads past packet buffer

Link for people: https://infrastack.ai/live/CVE-2026-125172 (this .md is for agents)

FFmpeg's libxevd decoder fails to check NAL unit length prefixes in EVC video, so a crafted file makes it read beyond the packet buffer. An attacker can crash the application or expose nearby heap memory.

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

## How to check

- Run `ffmpeg -version` to see the installed version, and compare it with the affected range through 9.0.2.
- Check whether the build includes the libxevd decoder (EVC support) with `ffmpeg -decoders | grep -i evc`.

## Timeline

- 2026-11-09T19:28:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125172

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-out-of-bounds-read-via-libxevd-evc-nal-length
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/e06b3953d4253f8b56271628ba4083fde96aeadb

## From the sources

FFmpeg through 9.0.2 contains an out-of-bounds read vulnerability in libxevd_receive_frame() in libavcodec/libxevd.c that fails to validate NAL unit length prefixes against remaining packet data. Attackers can supply crafted EVC media with oversized 4-byte NAL length prefixes, causing libxevd to read past the packet buffer, crashing the application or exposing adjacent heap memory.

---

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