#VU63878 Information disclosure in Mozilla Firefox and Firefox ESR - CVE-2022-31742

Vulnerability identifier: #VU63878

Vulnerability risk: Medium

CVSSv4.0: 4.6 [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-2022-31742

CWE-ID: CWE-200

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 gain access to potentially sensitive information.

The vulnerability exists due to an error when handling a large number of allowCredential entries. A remote attacker can trick the victim to visit a specially crafted website, launch a timing attack and detect the difference between invalid key handles and cross-origin key handles. Successful exploitation of the vulnerability can lead to cross-origin account linking in violation of WebAuthn goals.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 100.0.2

Firefox ESR: 91.0 - 91.9.1

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2022-20/
https://www.mozilla.org/en-US/security/advisories/mfsa2022-21/

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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.