What is CVE-2026-4926?

CVE-2026-4926 is a high-severity vulnerability in Path-to-regexp, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-03-26.

How severe is CVE-2026-4926?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Path-to-regexp

CVE-2026-4926

Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service…

Vulnerability class: DoS (Denial of Service)

EPSS: 0.000 (5.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Path-to-regexp — versions 8.0.0, 8.4.0

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption
CWE-1333 — Inefficient Regular Expression Complexity

References

cna.openjsf.org/security-advisories.html

Frequently asked questions

What is CVE-2026-4926?: CVE-2026-4926 is a high-severity vulnerability in Path-to-regexp, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-03-26.
How severe is CVE-2026-4926?: High severity. CVSS v3 base score is 7.5 out of 10.