InfoSec Signals™
Sign InStart Free
Back to CVE records
High 7.5Published Mar 26, 2026

CVE-2026-4926path-to-regexp vulnerable to Denial of Service via sequential optional groups

Updated under an hour ago ()

Does this affect you?

It affects path-to-regexp and 38 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

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. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

CVSS
7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-400, 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
Modified
Record last updated
Sep 17, 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
from 4.2.0-9 not affected
CISA ADP
from 0:2.5.20260422-3.el8ap not affected
CISA ADP
Red Hat Migration Toolkit for Virtualization 2.1
redhat:migration_toolkit_virtualization
from 1779139872 not affected
CISA ADP
from 1776784286 not affected
CISA ADP
from 1783502765 not affected
CISA ADP
Red Hat Red Hat Migration Toolkit for Applications 8.1
redhat:migration_toolkit_applications
from 1785169013 not affected
CISA ADP
from 1787801527 not affected
CISA ADP
from 1776744110 not affected
CISA ADP
Red Hat Red Hat OpenShift distributed tracing 3.9.3
redhat:openshift_distributed_tracing
from 1776435608 not affected
CISA ADP

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.

Your cookie choices
We use essential cookies to run this site, and, only with your consent, an advertising cookie from Google to measure whether our ads lead to sign-ups and subscriptions. See our for details.