pillarjs/path-to-regexp · Security
path-to-regexp vulnerable to Denial of Service via sequential optional groups
- GHSA ID
- GHSA-j3q9-mxjg-w52f
- CVE ID
- CVE-2026-4926
- Severity
- high
- Published
- Updated
- CVSS
- 7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CVSS v3
- 7.5 · CVSS: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.
CWEs
- CWE-400 · Uncontrolled Resource Consumption
- CWE-1333 · Inefficient Regular Expression Complexity