CVE-2026-4926 — Uncontrolled Resource Consumption in Path-to-regexp

CWE-400 — Uncontrolled Resource ConsumptionCWE-1333 — Regex Denial of Service9 documents7 sources
Severity
7.5HIGHNVD
EPSS
0.1%
top 83.75%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Path-to-regexpDebian Node-path-to-regexp
Timeline
PublishedMar 26
Latest updateMar 27

Description

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 vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages3 packages

▶debiandebian/node-path-to-regexp< node-path-to-regexp 8.4.0-1 (forky)
▶CVEListV5path-to-regexp/path-to-regexp8.0.0 — 8.4.0
▶npmpath-to-regexp/path-to-regexp8.0.0 — 8.4.0

🔴Vulnerability Details

3
OSV
path-to-regexp vulnerable to Denial of Service via sequential optional groups↗2026-03-27
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GHSA
path-to-regexp vulnerable to Denial of Service via sequential optional groups↗2026-03-27
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OSV
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`↗2026-03-26
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📋Vendor Advisories

2
Red Hat
path-to-regexp: path-to-regexp: Denial of Service via crafted regular expressions↗2026-03-26
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Debian
CVE-2026-4926: node-path-to-regexp - Impact: A bad regular expression is generated any time you have multiple sequen...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-4926 Impact, Exploitability, and Mitigation Steps | Wiz↗
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💬Community

1
Bugzilla
CVE-2026-4926 path-to-regexp: path-to-regexp: Denial of Service via crafted regular expressions↗2026-03-26
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