CVE-2026-4923CWE-1333

path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards

Medium · published March 26, 2026

CVSS v3.1
5.9
EPSS
0%
Percentile
29.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.9 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00371 · 29.8th percentile
Weakness
CWE-1333 · Inefficient Regular Expression Complexity
Published
2026-03-26T19:02Z
EPSS history
Timeline
  • 26 MAR 19:02Z
    path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards
    cvelistv5