CVE-2026-115913: vLLM Phi-4 multimodal audio encoder GPU memory exhaustion

CVE-2026-115913 · Severity: medium · CVSS 6.5 · Published 2026-10-26

vLLM is an inference engine for large language models that processes audio and other multimodal inputs. A remote attacker can send a single legitimate long audio file that causes the Phi-4 audio encoder to retain full attention matrices in GPU memory, exhausting GPU resources and crashing the service for all other users.

Technologies: vllm (PyPI), vLLM Project vllm. Vendors: PyPI, vLLM Project.

Quick answers

Is CVE-2026-115913 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-115913 being exploited in the wild.
How severe is CVE-2026-115913?
Medium severity, with a CVSS score of 6.5, published 26 October 2026.
Which products and versions are affected?
vllm (PyPI) < 0.32.0, ECOSYSTEM:introduced=0,fixed=0.32.0; vLLM Project vllm before 0.32.0.
Is there a fix for CVE-2026-115913?
Yes. vllm (PyPI): upgrade to 0.32.0 or later. Until then: Disable the eager attention path or explicitly configure the Phi-4 audio encoder to use PyTorch scaled-dot-product attention instead of eager attention evaluation. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-115913 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-115913?
Check whether you run vllm (PyPI) or vLLM Project vllm at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • vllm (PyPI): upgrade to 0.32.0 or later
    pip install "vllm>=0.32.0"

Disable the eager attention path or explicitly configure the Phi-4 audio encoder to use PyTorch scaled-dot-product attention instead of eager attention evaluation.

Technical details

The Phi-4 multimodal audio encoder in vLLM versions prior to 0.32.0 uses eager attention evaluation by default in MultiHeadedAttention.forward_attention(), which materializes and retains full attention probability matrices in memory across all 24 encoder layers. A remote client can send a maximal-length audio input that causes the conformer encoder to pin multi-gigabyte tensors, triggering GPU out-of-memory and terminating the EngineCore service. The scaled dot-product attention branch does not materialize these matrices; the fix switches the default to use PyTorch's scaled-dot-product attention and removes matrix retention from the eager path.

Affected products

  • vLLM Project vLLM before 0.32.0

Identifiers

  • CVE-2026-115913
  • GHSA-8397-8qf6-f2gm

Timeline

  • 2026-10-26: disclosed
  • 2026-10-09: patched

References

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