CVE-2026-4923
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards
- State
- Published
- Severity
- 5.9 Medium
- Published
- Mar 26, 2026
- Updated
- Mar 27, 2026
- Reserved
- Mar 26, 2026
Description
Impact:
When using multiple wildcards, combined with at least one parameter, a regular expression can be generated that is vulnerable to ReDoS. This backtracking vulnerability requires the second wildcard to be somewhere other than the end of the path.
Unsafe examples:
/*foo-*bar-:baz /*a-:b-*c-:d /x/*a-:b/*c/y
Safe examples:
/*foo-:bar /*foo-:bar-*baz
Patches:
Upgrade to version 8.4.0.
Workarounds:
If you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | openjs |
Weaknesses
- CWE-1333 Inefficient Regular Expression Complexity
Affected Products
| Product | Versions |
|---|---|
path-to-regexppath-to-regexp |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.