CVE-2026-73556
Medium · 5.3CVSS
5.3
EPSS
0.5%
Published
Aug 13, 2026
CISA due date
—
The record
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.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
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