CVE Catalog

CVE-2026-73556

MediumCVSS 5.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.52%

42th percentile - higher than 42% of all known CVEs

Summary

In vLLM prior to 0.26.0, the structured_outputs.regex parameter in vllm/v1/structured_output/backend_lm_format_enforcer.py is passed to lmformatenforcer.RegexParser without compile_regex_with_timeout or validation in validate_structured_output_request_lm_format_enforcer, allowing an unauthenticated /v1/completions request against the lm-format-enforcer backend to consume a CPU core and stall the structured-output engine path with a catastrophic regular expression. This issue is fixed in version 0.26.0.

Risk Assessment

The risk is the possibility of a DoS attack by an unauthenticated user, which could lead to service unavailability and CPU resource exhaustion.

Recommendation

It is recommended to upgrade vLLM to version 0.26.0 or later, which includes a fix for this vulnerability.

Other vulnerabilities in vLLM

See all
Original NVD description (English source)

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structured_outputs.regex parameter in vllm/v1/structured_output/backend_lm_format_enforcer.py is passed to lmformatenforcer.RegexParser without compile_regex_with_timeout or validation in validate_structured_output_request_lm_format_enforcer, allowing an unauthenticated /v1/completions request against the lm-format-enforcer backend to consume a CPU core and stall the structured-output engine path with a catastrophic regular expression. This issue is fixed in version 0.26.0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS