An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-16127
Reference (s):
- https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS
- URL: https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS