CVE-2025-59425: vllm-project vllm Covert Timing Channel

Vulnerability summary

CVE-2025-59425 is a high (CVSS 7.5) Covert Timing Channel vulnerability in vllm-project vllm. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 45.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 07-10-2025
   PublishedVulnerability first disclosed.
2. 07-10-2025
   Last modifiedVulnerability information updated.

Description

vLLM is an inference and serving engine for large language models (LLMs). Before version 0.11.0rc2, the API key support in vLLM performs validation using a method that was vulnerable to a timing attack. API key validation uses a string comparison that takes longer the more characters the provided API key gets correct. Data analysis across many attempts could allow an attacker to determine when it finds the next correct character in the key sequence. Deployments relying on vLLM's built-in API key validation are vulnerable to authentication bypass using this technique. Version 0.11.0rc2 fixes the issue.

• CWE-385Covert Timing ChannelCovert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.