CVE-2026-4923 Details
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.
A regular expression denial-of-service (ReDoS) vulnerability has been identified in the path-to-regexp library. This issue arises when multiple wildcards are used in conjunction with at least one parameter, creating a regular expression that can be exploited through backtracking. The vulnerability requires the second wildcard to be positioned away from the end of the path. Users can upgrade to version 8.4.0 to address this vulnerability. As a workaround, those using multiple wildcard parameters can verify the regex output with a tool like 'ReCheck' to ensure that a path is not vulnerable.
Users can upgrade to path-to-regexp version 8.4.0 to address this vulnerability. Instructions for upgrading can be found in the project's GitHub repository.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 27, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://cna.openjsf.org/security-advisories.html | openjs | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-1333 | Inefficient Regular Expression Complexity | openjs |
Affected Products
| Product | Versions |
|---|---|
| pillarjs path-to-regexp | >= 8.0.0, < 8.4.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | openjs |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 16, 2026 | Initial Analysis | [email protected] |
| Mar 26, 2026 | New CVE Received | openjs |