Vulnerability identifier: #VU48461

Vulnerability risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26953

CWE-ID: N/A

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to the way under certain conditions Firefox enters the fullscreen mode without displaying UI notification. A remote attacker can perform a phishing attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Firefox ESR: 78.0 - 78.4.1, 68.0 - 68.12.0, 60.0 - 60.9.0

Mozilla Firefox: 60.0 - 82.0.3

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/

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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.