Vulnerability · Published Aug 13, 2026 · Assigned by GitHub_M

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

Medium 5.3

In plain English

A medium-severity security flaw in vllm from vllm-project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 64.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	vllm	0.26.0	GHSA-hwrm-c4cx-rf4j
PyPI	vllm	0.26.0	PYSEC-2026-3937

Affected products (as reported)

Vendor	Product	Versions
vllm-project	vllm	< 0.26.0

Weakness: CWE-209 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

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