CVE-2021-39757: 
NixOS vulnerability analysis and mitigation

In PermissionController for Android 12L, there exists a permission bypass vulnerability (CVE-2021-39757) due to an unsafe PendingIntent. This vulnerability was discovered and disclosed in March 2022, affecting Android-12L systems. The issue could potentially lead to local information disclosure with User execution privileges, and notably does not require user interaction for exploitation (NVD).

The vulnerability has been assigned a CVSS v3.1 Base Score of 5.5 (MEDIUM) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. Under CVSS v2.0, it received a Base Score of 2.1 (LOW) with the vector (AV:L/AC:L/Au:N/C:P/I:N/A:N). The vulnerability specifically involves an unsafe PendingIntent in the PermissionController component, which could be exploited locally (NVD).

The successful exploitation of this vulnerability could lead to local information disclosure. The attack requires User execution privileges but does not need user interaction for exploitation. The impact is primarily focused on confidentiality, with no direct impact on integrity or availability of the system (NVD).

The vulnerability has been addressed in Android security updates. Users should ensure their Android devices are updated to the latest available security patch level that includes fixes for Android 12L (Android Advisory).