CVE-2026-125214: FFmpeg: heap overflow in Blu-ray PCM decoder (big-endian)

HIGH

Published November 9, 2026

CISO Take

FFmpeg through 9.0.2 has a heap buffer overflow in its Blu-ray LPCM audio decoder that triggers only on big-endian hosts when a crafted M2TS stream has a payload length that is not a multiple of the sample size. Exposure is narrow: the CVSS vector requires local access, high attack complexity and user interaction, there is no EPSS score, no public exploit, no Nuclei template, and it is not in CISA KEV or assessed by SSVC. Big-endian platforms (s390x, some PowerPC and MIPS builds) are rare in AI/ML fleets, so most media-ingestion pipelines are unaffected. Teams that run FFmpeg on such hosts to preprocess video or audio for training datasets or speech models should apply the upstream fix (commit a61b32df) or a release that contains it, and in the meantime avoid decoding untrusted M2TS/Blu-ray files there. Treat this as a routine patch-cycle item, not an emergency.

Sources:NVDVulnCheckATLAScode.ffmpeg.orggithub.com/FFmpeg

What is the risk?

Medium-to-low practical risk despite the High CVSS score of 7.0. The attack is local, needs high complexity and user interaction, and works only on big-endian architectures, which shrinks the exposed population. There is no known exploitation, no public PoC, and no KEV listing. Successful exploitation yields attacker-controlled out-of-bounds heap writes, which could in theory lead to code execution or a crash. Risk rises if a pipeline automatically decodes untrusted uploaded media on big-endian hardware, because that removes the user-interaction barrier in practice. Package risk data is unavailable (Package Risk Score 0/100, no scorecard), so downstream blast radius is unknown.

How does the attack unfold?

Initial Access

Attacker delivers a crafted M2TS file with malformed Blu-ray LPCM payload length through a dataset, upload or shared media.

AML.T0011

Exploitation

FFmpeg's pcm_bluray_decode_frame() on a big-endian host writes attacker-controlled bytes past the audio frame buffer.

AML.T0010.001

Impact

Heap corruption crashes the ingestion worker or enables code execution with access to pipeline data and credentials.

Initial Access

Attacker delivers a crafted M2TS file with malformed Blu-ray LPCM payload length through a dataset, upload or shared media.

AML.T0011

Exploitation

FFmpeg's pcm_bluray_decode_frame() on a big-endian host writes attacker-controlled bytes past the audio frame buffer.

AML.T0010.001

Impact

Heap corruption crashes the ingestion worker or enables code execution with access to pipeline data and credentials.

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
FFmpeg	—	—	No patch

Do you use FFmpeg? You're affected.

How severe is it?

CVSS 3.1

7.0 / 10

EPSS

0.1%

chance of exploitation in 30 days

Higher than 4% of all CVEs

Source: EPSS v3 — FIRST.org

Exploitation Status

No known exploitation

Sophistication

Advanced

What is the attack surface?

AVLocal

ACHigh

PRNone

UIRequired

SUnchanged

CHigh

IHigh

AHigh

What should I do?

1 step

1) Upgrade FFmpeg to a build that includes upstream commit a61b32df3fd67f76c1c8c7ea51be2a66efb0f945 or any release later than 9.0.2 that contains the fix; check distro and container base image updates. 2) Inventory big-endian hosts (s390x, ppc64 big-endian) that run FFmpeg or libavcodec through Python wrappers, OpenCV or media libraries. 3) Where patching is delayed, reject or quarantine M2TS/Blu-ray inputs, or disable the pcm_bluray decoder (for example with -allowed_decoders restrictions or a build without it). 4) Run media decoding in sandboxed, low-privilege containers with seccomp and memory limits. 5) Monitor for decoder crashes (SIGSEGV, heap corruption aborts) in ingestion workers and alert on repeated failures from the same input.

How is it classified?

Code ExecutionDoSSupply ChainFrameworkTraining DataAML.T0010.001- AI Software AML.T0011- User Execution

Which compliance frameworks are affected?

This CVE is relevant to:

ISO 42001

A.6.2.6-AI system operation and monitoring

NIST AI RMF

MANAGE 2.3-Respond to and recover from identified risks

OWASP LLM Top 10

LLM03-Supply Chain

Frequently Asked Questions

What is CVE-2026-125214?

Is CVE-2026-125214 actively exploited?

No confirmed active exploitation of CVE-2026-125214 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-125214?

1) Upgrade FFmpeg to a build that includes upstream commit a61b32df3fd67f76c1c8c7ea51be2a66efb0f945 or any release later than 9.0.2 that contains the fix; check distro and container base image updates. 2) Inventory big-endian hosts (s390x, ppc64 big-endian) that run FFmpeg or libavcodec through Python wrappers, OpenCV or media libraries. 3) Where patching is delayed, reject or quarantine M2TS/Blu-ray inputs, or disable the pcm_bluray decoder (for example with -allowed_decoders restrictions or a build without it). 4) Run media decoding in sandboxed, low-privilege containers with seccomp and memory limits. 5) Monitor for decoder crashes (SIGSEGV, heap corruption aborts) in ingestion workers and alert on repeated failures from the same input.

What systems are affected by CVE-2026-125214?

This vulnerability affects the following AI/ML architecture patterns: training data preprocessing pipelines, multimodal ingestion pipelines, speech and audio processing services, media transcoding workers.

What is the CVSS score for CVE-2026-125214?

CVE-2026-125214 has a CVSS v3.1 base score of 7.0 (HIGH). The EPSS exploitation probability is 0.14%.

What is the AI security impact?

Affected AI Architectures

training data preprocessing pipelinesmultimodal ingestion pipelinesspeech and audio processing servicesmedia transcoding workers

MITRE ATLAS Techniques

AML.T0010.001AI Software

AML.T0011User Execution

Compliance Controls Affected

ISO 42001: A.6.2.6

NIST AI RMF: MANAGE 2.3

OWASP LLM Top 10: LLM03

What are the technical details?

Original Advisory

FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in pcm_bluray_decode_frame() in libavcodec/pcm-bluray.c on big-endian hosts. Attackers can supply a crafted Blu-ray (M2TS) LPCM stream whose payload length is not a multiple of the sample size, writing attacker-controlled bytes past the audio frame buffer.

Exploitation Scenario

An attacker supplies a crafted M2TS file with a Blu-ray LPCM audio stream whose payload length is not a multiple of the sample size, for example as a poisoned video in a public dataset or an upload to a media-processing service. A data engineer or an automated preprocessing job on a big-endian host decodes the file with FFmpeg. The decoder writes attacker-controlled bytes past the audio frame buffer, corrupting the heap. The attacker may crash the pipeline or, with further effort, hijack the worker process and reach dataset storage or credentials.

Weaknesses (CWE)

CWE-122Heap-based Buffer Overflow

CWE-122 — Heap-based Buffer Overflow: The product writes past the end of a buffer that was allocated on the heap.

Pre-design: Use a language or compiler that performs automatic bounds checking.
[Architecture and Design] Use an abstraction library to abstract away risky APIs. Not a complete solution.

Source: MITRE CWE corpus.