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CVE-2026-73556

CVE-2026-73556 · vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of CVE-2026-55574

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 5.3 · Medium · EPSS 0.5% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • vllm

    Versions
    • < 0.26.0: Affected

    No fix published

  • vllm PyPI

    Versions
    • 0.0.1
    • 0.1.0
    • 0.1.1
    • 0.1.2
    • 0.1.3
    • 0.1.4
    • 0.1.5
    • 0.1.6
    • 0.1.7
    • 0.10.0
    • 0.10.1
    • 0.10.1.1
    • 0.10.2
    • 0.11.0
    • 0.11.1
    • 0.11.2
    • 0.12.0
    • 0.13.0
    • 0.14.0
    • 0.14.1
    • 0.15.0
    • 0.15.1
    • 0.16.0
    • 0.17.0
    • 0.17.1
    • 0.18.0
    • 0.18.1
    • 0.19.0
    • 0.19.1
    • 0.2.0
    • 0.2.1
    • 0.2.1.post1
    • 0.2.2
    • 0.2.3
    • 0.2.4
    • 0.2.5
    • 0.2.6
    • 0.2.7
    • 0.20.0
    • 0.20.1
    • 0.20.2
    • 0.21.0
    • 0.22.0
    • 0.22.1
    • 0.23.0
    • 0.24.0
    • 0.25.0
    • 0.25.1
    • 0.3.0
    • 0.3.1
    • 0.3.2
    • 0.3.3
    • 0.4.0
    • 0.4.0.post1
    • 0.4.1
    • 0.4.2
    • 0.4.3
    • 0.5.0
    • 0.5.0.post1
    • 0.5.1
    • 0.5.2
    • 0.5.3
    • 0.5.3.post1
    • 0.5.4
    • 0.5.5
    • 0.6.0
    • 0.6.1
    • 0.6.1.post1
    • 0.6.1.post2
    • 0.6.2
    • 0.6.3
    • 0.6.3.post1
    • 0.6.4
    • 0.6.4.post1
    • 0.6.5
    • 0.6.6
    • 0.6.6.post1
    • 0.7.0
    • 0.7.1
    • 0.7.2
    • 0.7.3
    • 0.8.0
    • 0.8.1
    • 0.8.2
    • 0.8.3
    • 0.8.4
    • 0.8.5
    • 0.8.5.post1
    • 0.9.0
    • 0.9.0.1
    • 0.9.1
    • 0.9.2
    Affected ranges
    • ECOSYSTEM: < 0.26.0

    Update to 0.26.0

Original sources

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