CVE-2018-12371: 
NixOS vulnerability analysis and mitigation

CVE-2018-12371 is an integer overflow vulnerability discovered in the Skia library that affects Firefox ESR < 60.1, Thunderbird < 60, and Firefox < 61. The vulnerability was identified in June 2018 and specifically occurs when allocating memory for edge builders on systems with at least 16 GB of RAM (Mozilla Advisory).

The vulnerability manifests as an integer overflow in the Skia library's SkEdgeBuilder component when allocating memory for edge builders. The issue occurs specifically on systems with at least 16 GB of RAM, where the overflow leads to the use of uninitialized memory. The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (HIGH) with vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (NVD).

When exploited, this vulnerability results in the use of uninitialized memory, which can lead to a potentially exploitable crash. The issue affects multiple Mozilla products including Firefox, Firefox ESR, and Thunderbird, potentially allowing attackers to execute arbitrary code (Mozilla Advisory).

The vulnerability requires user interaction and can be triggered through specially crafted web content. A proof of concept was developed that demonstrates the vulnerability can be triggered in less than 10 minutes on systems with sufficient RAM (Mozilla Bug).

Mozilla addressed this vulnerability by implementing validation for SkArenaAlloc sizes to catch overflows through release asserts. The fix was included in Firefox 61, Firefox ESR 60.1, and Thunderbird 60. Users are advised to upgrade to these or later versions to mitigate the vulnerability (Mozilla Advisory).