SB2026072871 - Inefficient regular expression complexity in vLLM

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Main Vulnerability Database SB2026072871

SB2026072871 - Inefficient regular expression complexity in vLLM

Published: July 28, 2026

Security Bulletin ID SB2026072871
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Partial DoS

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Inefficient regular expression complexity (CVE-ID: N/A)

CWE-ID: CWE-1333 - Inefficient Regular Expression Complexity

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to inefficient regular expression complexity in the lm-format-enforcer structured output backend when compiling attacker-supplied regular expressions. A remote attacker can send a specially crafted request containing a catastrophic regular expression to cause a denial of service.

Exploitation requires the operator to have selected the lm-format-enforcer backend for structured outputs.


Remediation

Install update from vendor's website.

References