CVE-2026-125263
Received Received - Intake

Heap-based Buffer Overflow in FFmpeg with LCEVC Decoder

Publication date: 2026-11-09

Last updated on: 2026-11-09

Assigner: VulnCheck

Description
FFmpeg 9.0 through 9.0.2 built with liblcevc_dec fails to validate LCEVC enhanced output dimensions against max_pixels in libavcodec/decode.c before frame allocation. Attackers can supply crafted H.264, HEVC or VVC streams declaring huge LCEVC resolutions to force oversized get_buffer2() allocations and exhaust memory.

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Meta Information

Published
2026-11-09
Last Modified
2026-11-09
Generated
2026-11-10
AI Q&A
2026-11-09
EPSS Evaluated
N/A
NVD
CVE-2026-125263
EUVD
EUVD-2026-120213

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
FFmpeg FFmpeg From 9.0 (inc) to 9.0.2 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-789 The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

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Executive Summary

This vulnerability affects FFmpeg versions 9.0 to 9.0.2 when built with liblcevc_dec. It fails to validate LCEVC enhanced output dimensions against max_pixels before frame allocation. Attackers can exploit this by providing specially crafted H.264, HEVC, or VVC video streams that declare extremely large LCEVC resolutions. This forces oversized memory allocations during frame buffer creation, potentially exhausting system memory.

Detection Guidance

This vulnerability involves oversized memory allocations due to crafted H.264, HEVC, or VVC streams with huge LCEVC resolutions. Detection requires monitoring for abnormal memory usage or crashes during media processing. Check FFmpeg logs for allocation failures or excessive memory consumption when decoding affected streams.

Impact Analysis

If exploited, this vulnerability could lead to denial-of-service conditions by consuming excessive system memory. It may cause applications using FFmpeg to crash or become unresponsive. Systems with limited memory resources are particularly vulnerable. The impact is local as it requires attacker-controlled media files.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by enabling denial-of-service attacks through memory exhaustion. GDPR requires data processing systems to ensure availability and integrity of personal data, while HIPAA mandates safeguards against unauthorized access or disruptions. Memory exhaustion could disrupt system availability, potentially violating these requirements.

Mitigation Strategies

Upgrade FFmpeg to a patched version that validates LCEVC output dimensions against max_pixels before frame allocation. Avoid processing untrusted media files, especially those with unusual resolutions. Monitor system memory usage for signs of exploitation attempts.

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