#VU60406 Sandbox restrictions bypass in Mozilla Firefox and Firefox ESR - CVE-2022-22759

Vulnerability identifier: #VU60406

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2022-22759

CWE-ID: CWE-264

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 bypass implemented security restrictions.

The vulnerability exists due to the way iframes are handled by the browser. If a document created a sandboxed iframe without allow-scripts, and subsequently appended an element to the iframe's document that e.g. had a JavaScript event handler - the event handler would have run despite the iframe's sandbox.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 70.0 - 96.0.3

Firefox ESR: 78.0 - 78.15.0, 91.0 - 91.5.1

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2022-04/
https://www.mozilla.org/en-US/security/advisories/mfsa2022-05/

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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.