Improper Link Resolution Before File Access ('Link Following')
The chkstat tool in the permissions package followed symlinks before commit a9e1d26cd49ef9ee0c2060c859321128a6dd4230 (please also check the additional hardenings after this fix). This allowed local attackers with control over a path that is traversed by chkstat to escalate privileges.
CWE-59 - Improper Link Resolution Before File Access
'Improper link resolution before file access' occurs when software accesses a file resource but fails to verify that the file isn't a link or shortcut to another file. An attacker can potentially gain access to arbitrary files and from there the impact can vary, depending on the application, from sensitive data exposure to remote code execution.