CVE-2020-15673: 
NixOS vulnerability analysis and mitigation

CVE-2020-15673 is a memory safety vulnerability discovered in Mozilla Firefox 80, Firefox ESR 78.2, and Thunderbird 78.2. The vulnerability was reported by Mozilla developer Jason Kratzer and was disclosed on September 22, 2020. The affected software versions include Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3 (Mozilla Advisory).

The vulnerability involves memory safety bugs that showed evidence of memory corruption. These bugs were present in Firefox 80 and Firefox ESR 78.2, with the potential for exploitation if sufficient effort was applied. The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (High), with attack vector being Network, attack complexity Low, and requiring user interaction (Ubuntu CVE).

The vulnerability could potentially allow an attacker to execute arbitrary code on affected systems. In Thunderbird specifically, while these flaws cannot typically be exploited through email due to disabled scripting when reading mail, they remain potential risks in browser or browser-like contexts (Mozilla Advisory).

The memory safety bugs showed evidence of memory corruption, and Mozilla security researchers presumed that with enough effort, these could have been exploited to run arbitrary code. The vulnerability requires user interaction for exploitation (Mozilla Advisory).

The vulnerability has been fixed in Firefox 81, Firefox ESR 78.3, and Thunderbird 78.3. Users are advised to upgrade to these versions or later. For Debian users, the fix was provided in version 1:78.3.1-2~deb10u2 for the stable distribution (buster) (Debian Advisory).