#VU50881 Improperly implemented security check for standard in Mozilla Firefox and Firefox ESR - CVE-2021-23968

Vulnerability identifier: #VU50881

Vulnerability risk: Medium

CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

CVE-ID: CVE-2021-23968

CWE-ID: CWE-358

Exploitation vector: Remote access

Exploit availability: No public exploit available

Vulnerable software:
Mozilla Firefox
Firefox ESR

Software vendor:
Mozilla

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

The vulnerability exists due to incorrect implementation of W3C Content Security Policy. If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. A remote attacker can gain knowledge of sensitive information contained in such URIs.

Install updates from vendor's website.

• https://www.mozilla.org/en-US/security/advisories/mfsa2021-07/
• https://www.mozilla.org/en-US/security/advisories/mfsa2021-08/