PatchTheCVECVE-2026-73556: vLLM is an inference and serving engine for large language models
CVE-2026-73556 is a medium-severity flaw (CVSS 5.3) affecting vllm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 st
Why this priority
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Last updated 2026-09-28 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-73556?
vllm: upgrade to 0.26.0. Exact commands for each OS are on this page.
Is CVE-2026-73556 being exploited?
CVE-2026-73556 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-73556 affect?
CVE-2026-73556 affects vllm. Severity is medium (CVSS 5.3). 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_
How urgent is CVE-2026-73556?
Priority 34/100. Remotely exploitable, no login, no user action
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