Integer overflow in Vllm-Project Vllm

CVE-2026-73558

vLLM is an inference and serving engine for large language models. Prior to 0.27.0, an integer overflow in blockIdx.x * 2 * d in activation_kernels.cu can cause act_and_mul_kernel to consume another batched user's input, allowing a request processed in the same inference batch to receive a partial or complete copy of another user's inference result. This issue is fixed in version 0.27.0.

Vulnerability class: Integer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (32.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 32.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-73558: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-73558?
CVE-2026-73558 is a medium-severity vulnerability in Vllm-Project Vllm, classified under Integer Overflow or Wraparound. CVSS score: 5.3/10. Published 2026-08-13.
How severe is CVE-2026-73558?
Medium severity. CVSS v3 base score is 5.3 out of 10.