Vulnerability identifier: #VU58607

Vulnerability risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-43538

CWE-ID: CWE-451

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to a race in notification code. A remote attacker can hide the notification for pages that had received full screen and pointer lock access. Successful exploitation of the vulnerability may allow an attacker to perform spoofing attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
http://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.