CVE-2021-23438: Mpath Project Mpath

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

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.

Affected products

• Mpath Project Mpath: before 0.8.4 (fixed in 0.8.4)

Published 2021-09-01. Last modified 2026-06-17.