VULNERABILITY INTELLIGENCE

CVE-2026-4926

CVSS score7.5 HIGH
EPSS probability0.80%
CISA KEVNot currently listed
Published2026-03-26
Last modified2026-09-09
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Weakness classification

  • ce714d77-add3-4f53-aff5-83d477b104bb: CWE-400
  • 0b0ca135-0b70-47e7-9f44-1890c2a1c46c: CWE-1333

Primary references