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.

The _expand_arg function in the pam_env module (modules/pam_env/pam_env.c) in Linux-PAM (aka pam) before 1.1.5 does not properly handle when environment variable expansion can overflow, which allows local users to cause a denial of service (CPU consumption).

Stack-based buffer overflow in the _assemble_line function in modules/pam_env/pam_env.c in Linux-PAM (aka pam) before 1.1.5 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via a long string of white spaces at the beginning of the ~/.pam_environment file.

The pam_env module in Linux-PAM (aka pam) 1.1.2 and earlier reads the .pam_environment file in a user's home directory, which might allow local users to run programs with an unintended environment by executing a program that relies on the pam_env PAM check.

The check_acl function in pam_xauth.c in the pam_xauth module in Linux-PAM (aka pam) 1.1.2 and earlier does not verify that a certain ACL file is a regular file, which might allow local users to cause a denial of service (resource consumption) via a special file.

The pam_sm_close_session function in pam_xauth.c in the pam_xauth module in Linux-PAM (aka pam) 1.1.2 and earlier does not properly handle a failure to determine a certain target uid, which might allow local users to delete unintended files by executing a program that relies on the pam_xauth PAM check.

pam_namespace.c in the pam_namespace module in Linux-PAM (aka pam) before 1.1.3 uses the environment of the invoking application or service during execution of the namespace.init script, which might allow local users to gain privileges by running a setuid program that relies on the pam_namespace PAM check, as demonstrated by the sudo program.

The (1) pam_env and (2) pam_mail modules in Linux-PAM (aka pam) before 1.1.2 use root privileges during read access to files and directories that belong to arbitrary user accounts, which might allow local users to obtain sensitive information by leveraging this filesystem activity, as demonstrated by a symlink attack on the .pam_environment file in a user's home directory.

The run_coprocess function in pam_xauth.c in the pam_xauth module in Linux-PAM (aka pam) before 1.1.2 does not check the return values of the setuid, setgid, and setgroups system calls, which might allow local users to read arbitrary files by executing a program that relies on the pam_xauth PAM check.

Linux-PAM before 1.0.4 does not enforce the minimum password age (MINDAYS) as specified in /etc/shadow, which allows local users to bypass intended security policy and change their passwords sooner than specified.

Integer signedness error in the _pam_StrTok function in libpam/pam_misc.c in Linux-PAM (aka pam) 1.0.3 and earlier, when a configuration file contains non-ASCII usernames, might allow remote attackers to cause a denial of service, and might allow remote authenticated users to obtain login access with a different user's non-ASCII username, via a login attempt.