A flaw was found in linux-pam. The module pam_namespace may use access user-controlled paths without proper protection, allowing local users to elevate their privileges to root via multiple symlink attacks and race conditions.

linux-pam (aka Linux PAM) before 1.6.0 allows attackers to cause a denial of service (blocked login process) via mkfifo because the openat call (for protect_dir) lacks O_DIRECTORY.

A flaw was found in pam_access, where certain rules in its configuration file are mistakenly treated as hostnames. This vulnerability allows attackers to trick the system by pretending to be a trusted hostname, gaining unauthorized access. This issue poses a risk for systems that rely on this feature to control who can access certain services or terminals.

A vulnerability was found in PAM. The secret information is stored in memory, where the attacker can trigger the victim program to execute by sending characters to its standard input (stdin). As this occurs, the attacker can train the branch predictor to execute an ROP chain speculatively. This flaw could result in leaked passwords, such as those found in /etc/shadow while performing authentications.

The Linux-PAM package before 1.5.2-6.1 for openSUSE Tumbleweed allows authentication bypass for SSH logins. The pam_access.so module doesn't correctly restrict login if a user tries to connect from an IP address that is not resolvable via DNS. In such conditions, a user with denied access to a machine can still get access. NOTE: the relevance of this issue is largely limited to openSUSE Tumbleweed and openSUSE Factory; it does not affect Linux-PAM upstream.