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Medium 5.9Published Mar 26, 2026

CVE-2026-4923path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards

Updated under an hour ago ()

Does this affect you?

It affects path-to-regexp and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-1333
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
openjs
NVD analysis
Analyzed
Record last updated
Mar 27, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
path-to-regexp path-to-regexp
path_to_regexp:path_to_regexp (from the name)
from 8.0.0 before 8.4.0; 8.4.0 not affected
CNA record
pillarjs path-to-regexp
pillarjs:path-to-regexp
from 8.0.0 before 8.4.0
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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