What’s Vulnerable › Vulnerabilities

CVE-2026-73555: vLLM: Unauthenticated Internal Path and Username Disclosure via Validation Error Messages

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-13 · updated 2026-10-02
• Weakness: CWE-209

Description

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the validation_exception_handler in vllm/entrypoints/openai/server_utils.py converts FastAPI RequestValidationError objects with str(exc), and sanitize_message in vllm/entrypoints/utils.py does not remove traceback-style file paths, allowing unauthenticated malformed JSON requests to /v1/chat/completions, /v1/completions, /tokenize, and /detokenize to disclose the OS username, home and virtual-environment paths, Python version, internal package structure, line numbers, and endpoint handler names. This issue is fixed in version 0.26.0.

Affected products

• vllm-project vllm: before 0.26.0 — fixed in 0.26.0

How to fix

Upgrade to a fixed version: vllm-project vllm 0.26.0. Check the vendor advisory for mitigations.

References

• https://github.com/vllm-project/vllm/commit/e87521626febe2763f997691d1599de4175f4324
• https://github.com/vllm-project/vllm/pull/46415
• https://github.com/vllm-project/vllm/releases/tag/v0.26.0
• https://github.com/vllm-project/vllm/security/advisories/GHSA-hwrm-c4cx-rf4j

Get alerted when CVE-2026-73555 or the next vulnerability affects your stack