Medium severity · published Mar 26, 2026
CVE-2026-4923
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards
5.9
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 29% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PA
path-to-regexp · path-to-regexp
8.0.0 before 8.4.0 · source: vendor, NVD
Affected product
PA
path-to-regexp
path-to-regexp
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path-to-regexp vulnerable to Denial of Service via sequential optional groups
7.5
CVE-2026-4867
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple route parameters