#VU50022 Type Confusion in Mozilla Firefox and Firefox ESR

Published: 2021-01-26

Vulnerability identifier: #VU50022

Vulnerability risk: High


CVE-ID: CVE-2021-23954


Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers

Vendor: Mozilla


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a type confusion error when using the new logical assignment operators in a JavaScript switch statement. A remote attacker can create a specially crafted web page, trick the victim into opening it, trigger a type confusion error and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 84.0.2

Firefox ESR: 78.0 - 78.6.1, 68.0 - 68.12.0, 60.0 - 60.9.0


External links

Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?

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