Vulnerability identifier: #VU67502

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-2022-40958

CWE-ID: CWE-254

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers
Firefox for Android
Mobile applications / Apps for mobile phones

Vendor: Mozilla

Description

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

The vulnerability exists due to incorrect handling of cookies. A remote attacker with access to a shared subdomain can inject a cookies with certain special characters, bypass Secure Context restriction for cookies with __Host and __Secure prefix and overwrite these cookies, potentially allowing session fixation attacks. 

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 104.0.2

Firefox ESR: 102.0 - 102.2.0, 91.0 - 91.13.0

Firefox for Android: 100.1.0 - 104.2.0

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2022-40/
http://www.mozilla.org/en-US/security/advisories/mfsa2022-41/

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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.