Vulnerability identifier: #VU56372

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-38491

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to Mixed-Content-Blocking was unable to check opaque origins. As a result, the mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 80.0 - 91.0.2

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2021-38/

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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.