CVE-2024-0751: 
NixOS vulnerability analysis and mitigation

CVE-2024-0751 is a privilege escalation vulnerability discovered in Mozilla Firefox, Firefox ESR, and Thunderbird that allows a malicious devtools extension to escalate privileges. The vulnerability affects Firefox versions before 122, Firefox ESR versions before 115.7, and Thunderbird versions before 115.7. This security issue was disclosed on January 23, 2024, and was reported by Rob Wu (Mozilla Advisory).

The vulnerability stems from incomplete access checks in the devtools.inspectedWindow.eval functionality. The security flaw allows a malicious devtools extension to bypass scheme-based restrictions, including access to moz-extension URLs and restricted domains. The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, indicating high severity with potential for complete compromise of confidentiality, integrity, and availability (NVD).

The vulnerability could allow an attacker to execute privileged code through a malicious devtools extension, potentially leading to unauthorized access to restricted documents, including other extensions and sensitive domains like addons.mozilla.org that should never be scriptable by any extension (Mozilla Bug).

The vulnerability has been fixed in Firefox 122, Firefox ESR 115.7, and Thunderbird 115.7. Users are strongly advised to upgrade to these versions or later to mitigate the risk. The fix implements more precise access checks comparable to content scripts and replaces the previous denylist-based approach with an allowlist-based security model (Debian Advisory).