CVSS 3.1
5.9 mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-4923
Medium (5.9) in pillarjs path-to-regexp. EPSS 0.4% chance of exploitation in the next 30 days. Fixed in path-to-regexp 8.4.0.
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.
Severity
- EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 29% of CVEs (scores of 2026-10-31)
- CWE
- CWE-1333
- Published
- Modified
- Record from
- the NVD, synced
Affected
- pillarjs:path-to-regexp
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-27v5-c462-wpq7 | npm | path-to-regexp | >=8.0.0 <8.4.0 | 8.4.0 |