express-4.22.1.tgz: 1 vulnerabilities (highest severity is: 7.5)

[mend-for-github-com]

Vulnerable Library - express-4.22.1.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/path-to-regexp/package.json

Found in HEAD commit: 2ff65424c48b6f26c40b741a18dfe5db8d9c8841

Vulnerabilities

Vulnerability	Severity	CVSS	Exploit Maturity	EPSS	Dependency	Type	Fixed in (express version)	Remediation Possible**	Reachability
CVE-2026-4867	High	7.5	Not Defined	0.1%	path-to-regexp-0.1.12.tgz	Transitive	N/A*	❌

*For some transitive vulnerabilities, there is no version of direct dependency with a fix. Check the "Details" section below to see if there is a version of transitive dependency where vulnerability is fixed.

**In some cases, Remediation PR cannot be created automatically for a vulnerability despite the availability of remediation

Details

CVE-2026-4867

Vulnerable Library - path-to-regexp-0.1.12.tgz

Express style path to RegExp utility

Library home page: https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-0.1.12.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/path-to-regexp/package.json

Dependency Hierarchy:

• express-4.22.1.tgz (Root Library)
  • ❌ path-to-regexp-0.1.12.tgz (Vulnerable Library)

Found in HEAD commit: 2ff65424c48b6f26c40b741a18dfe5db8d9c8841

Found in base branch: main

Vulnerability Details

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 path-to-regexp@0.1.12 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 path-to-regexp@0.1.13
Custom regex patterns in route definitions (e.g., /:a-:b([^-/]+)-:c([^-/]+)) are not affected because they override the default capture group.
Workarounds:
All versions can be patched by providing a custom regular expression for parameters after the first in a single segment. As long as the custom regular expression does not match the text before the parameter, you will be safe. For example, change /:a-:b-:c to /:a-:b([^-/]+)-:c([^-/]+).
If paths cannot be rewritten and versions cannot be upgraded, another alternative is to limit the URL length.

Publish Date: 2026-03-26

URL: CVE-2026-4867

Threat Assessment

Exploit Maturity: Not Defined

EPSS: 0.1%

CVSS 3 Score Details (7.5)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: High

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Origin: GHSA-37ch-88jc-xwx2

Release Date: 2026-03-26

Fix Resolution: path-to-regexp - 0.1.13

[mend-for-github-com]

✔️ This issue was automatically closed by Mend because the vulnerable library in the specific branch(es) was either marked as ignored or it is no longer part of the Mend inventory.

[mend-for-github-com]

ℹ️ This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.

[mend-for-github-com]

✔️ This issue was automatically closed by Mend because the vulnerable library in the specific branch(es) was either marked as ignored or it is no longer part of the Mend inventory.

[mend-for-github-com]

ℹ️ This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.