CVE-2021-23954

Mozilla: Type confusion when using logical assignment operators in JavaScript switch statements

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Severity

Important

Red Hat Product Security

8.8

CVSS 3.1

Review impact separately from score.

Published · January 26, 2021

Updated · November 22, 2025

Description

The Mozilla Foundation Security Advisory describes this flaw as:

Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion, leading to a memory corruption and a potentially exploitable crash.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE-843 · Access of Resource Using Incompatible Type ('Type Confusion')