CVE-2026-4867 — Regex Denial of Service in Path-to-regexp

CWE-1333 — Regex Denial of Service7 documents6 sources
Severity
7.5HIGHNVD
EPSS
0.1%
top 84.82%
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 three or more parameters within a single segment, separated by something that is not a period (.). For example, /:a-:b-:c or /:a-:b-:c-:d. The backtrack protection added in [email protected] only prevents ambiguity for two parameters. With three or more, the generated lookahead does not block single separator characters, so capture groups overlap and cause catastrophic backtracking. Patches: Upgrade to [email protected] …

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 1.0.1-1 (bookworm)
▶CVEListV5path-to-regexp/path-to-regexp< 0.1.13

🔴Vulnerability Details

3
OSV
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple route parameters↗2026-03-27
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GHSA
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple route parameters↗2026-03-27
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OSV
CVE-2026-4867: Impact: A bad regular expression is generated any time you have three or more parameters within a single segment, separated by something that is not a↗2026-03-26
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📋Vendor Advisories

2
Red Hat
path-to-regexp: path-to-regexp: Denial of Service via catastrophic backtracking from malformed URL parameters↗2026-03-26
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Debian
CVE-2026-4867: node-path-to-regexp - Impact: A bad regular expression is generated any time you have three or more p...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-4867 Impact, Exploitability, and Mitigation Steps | Wiz↗
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