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.

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.

The _unix_run_helper_binary function in the pam_unix module in Linux-PAM (aka pam) before 1.2.1, when unable to directly access passwords, allows local users to enumerate usernames or cause a denial of service (hang) via a large password.

Multiple directory traversal vulnerabilities in pam_timestamp.c in the pam_timestamp module for Linux-PAM (aka pam) 1.1.8 allow local users to create arbitrary files or possibly bypass authentication via a .. (dot dot) in the (1) PAM_RUSER value to the get_ruser function or (2) PAM_TTY value to the check_tty function, which is used by the format_timestamp_name function.