CVE-2026-109311
Received Received - Intake

vLLM Heap Overflow via Malformed IAMF Upload

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
vLLM before 0.29.0 passes uploaded audio to the PyAV/FFmpeg av.open() fallback with only a file-size check, exposing FFmpeg's IAMF parser heap overflow. Authenticated remote attackers can repeatedly upload malformed IAMF containers to /v1/audio/transcriptions, corrupting the heap and crashing the API process.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-109311
EUVD
EUVD-2026-97613

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
vllm-project vllm 0

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-20 The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

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Executive Summary

CVE-2026-109311 is a heap overflow vulnerability in vLLM versions before 0.29.0. It occurs when malformed IAMF audio files are uploaded to the /v1/audio/transcriptions endpoint. The system only checks file size before processing, passing the file to PyAV/FFmpeg's av.open() which triggers a heap overflow in FFmpeg's IAMF parser.

Detection Guidance

Monitor vLLM API logs for repeated failed audio transcription requests or crashes. Check for malformed IAMF file uploads to /v1/audio/transcriptions endpoints. Use network traffic analysis tools to detect unusual audio file upload patterns targeting transcription services.

Impact Analysis

Authenticated remote attackers can exploit this to crash the vLLM API process by repeatedly uploading malicious IAMF files. This causes a denial of service, disrupting transcription services for all users. The impact is limited to availability and requires access to the transcription endpoint.

Mitigation Strategies

Upgrade vLLM to version 0.29.0 or later. Implement input validation for IAMF files before processing. Restrict access to the /v1/audio/transcriptions endpoint. Monitor API processes for crashes and restart them if necessary.

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