CVE-2021-23438

Name: CVE-2021-23438
Creator: NVD / NIST
Published: 2021-09-01T19:15:07.44+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.72%

Last modified Jun 17, 2026

CVE-2021-23438 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. This affects the package mpath before 0.8.4. A type confusion vulnerability can lead to a bypass of CVE-2018-16490. EPSS estimates a 1.72% chance of exploitation in the next 30 days.

Description

This affects the package mpath before 0.8.4. A type confusion vulnerability can lead to a bypass of CVE-2018-16490. In particular, the condition ignoreProperties.indexOf(parts[i]) !== -1 returns -1 if parts[i] is ['__proto__']. This is because the method that has been called if the input is an array is Array.prototype.indexOf() and not String.prototype.indexOf(). They behave differently depending on the type of the input.

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

1.72%

74.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-843

Affected Software

Vendor	Product	Versions
Mpath Project	Mpath	< 0.8.4

References

https://github.com/aheckmann/mpath/commit/89402d2880d4ea3518480a8c9847c541f2d824fcPatch, Third Party Advisory
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1579548Exploit, Third Party Advisory
https://snyk.io/vuln/SNYK-JS-MPATH-1577289Exploit, Third Party Advisory
https://github.com/aheckmann/mpath/commit/89402d2880d4ea3518480a8c9847c541f2d824fcPatch, Third Party Advisory
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1579548Exploit, Third Party Advisory
https://snyk.io/vuln/SNYK-JS-MPATH-1577289Exploit, Third Party Advisory

Timeline

Published: Sep 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23438?

How severe is CVE-2021-23438?

CVE-2021-23438 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.72% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23438?

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-2021-23438?

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

Scan your code now

Source: NVD / NIST