CVE-2026-4926
HIGH
NVD
CVSS Score
7.5
Severity
HIGH
Published
Mar 26, 2026
Vendor
unknown
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.