CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LCVE-2026-73556
Medium (5.3) in vllm vllm. EPSS 0.5% chance of exploitation in the next 30 days. Fixed in vllm 0.26.0.
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.
Severity
- EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 43% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-400, CWE-1333
- Published
- Modified
- Record from
- the NVD, synced
Affected
- vllm:vllm
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-48jh-3gj7-fg8v | PyPI | vllm | <0.26.0 | 0.26.0 |
| PYSEC-2026-3933 | PyPI | vllm | <0.26.0 | 0.26.0 |
References
- https://github.com/vllm-project/vllm/commit/c9a788eedc412acceaa5112e0d44624b49841577
- https://github.com/vllm-project/vllm/pull/47595
- https://github.com/vllm-project/vllm/releases/tag/v0.26.0
- https://github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8v
- https://github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8v