CVE-2021-23518

Name: CVE-2021-23518
Creator: NVD / NIST
Published: 2022-01-21T20:15:07.963+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.94%

Last modified Jun 17, 2026

CVE-2021-23518 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. The package cached-path-relative before 1.1.0 are vulnerable to Prototype Pollution via the cache variable that is set as {} instead of Object.create(null) in the cachedPathRelative function, which allows access to the parent prototype properties when the object is used to create the cached relative path. When using the origin path as __proto__, the attribute of the object is accessed instead of a path. EPSS estimates a 1.94% chance of exploitation in the next 30 days.

Description

The package cached-path-relative before 1.1.0 are vulnerable to Prototype Pollution via the cache variable that is set as {} instead of Object.create(null) in the cachedPathRelative function, which allows access to the parent prototype properties when the object is used to create the cached relative path. When using the origin path as __proto__, the attribute of the object is accessed instead of a path. **Note:** This vulnerability derives from an incomplete fix in https://security.snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-72573

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.94%

77.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1321

Affected Software

Vendor	Product	Versions
Cached-Path-Relative Project	Cached-Path-Relative	< 1.1.0
Debian	Debian Linux	10.0

References

https://github.com/ashaffer/cached-path-relative/commit/40c73bf70c58add5aec7d11e4f36b93d144bb760Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/12/msg00006.htmlMailing List, Third Party Advisory
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-2348246Exploit, Issue Tracking, Patch, Third Party Advisory
https://snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-2342653Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/ashaffer/cached-path-relative/commit/40c73bf70c58add5aec7d11e4f36b93d144bb760Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/12/msg00006.htmlMailing List, Third Party Advisory
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-2348246Exploit, Issue Tracking, Patch, Third Party Advisory
https://snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-2342653Exploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Jan 21, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23518?

How severe is CVE-2021-23518?

CVE-2021-23518 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.94% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23518?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-23518?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST