The Debian shadow package before 1:4.5-1 for Shadow incorrectly lists pts/0 and pts/1 as physical terminals in /etc/securetty. This allows local users to login as password-less users even if they are connected by non-physical means such as SSH (hence bypassing PAM's nulloksecure configuration). This notably affects environments such as virtual machines automatically generated with a default blank root password, allowing all local users to escalate privileges.

Privilege escalation can occur in the SUSE useradd.c code in useradd, as distributed in the SUSE shadow package through 4.2.1-27.9.1 for SUSE Linux Enterprise 12 (SLE-12) and through 4.5-5.39 for SUSE Linux Enterprise 15 (SLE-15). Non-existing intermediate directories are created with mode 0777 during user creation. Given that they are world-writable, local attackers might use this for privilege escalation and other unspecified attacks. NOTE: this would affect non-SUSE users who took useradd.c code from a 2014-04-02 upstream pull request; however, no non-SUSE distribution is known to be affected.

Multiple CRLF injection vulnerabilities in (1) chfn and (2) chsh in shadow 1:4.1.4 allow local users to add new users or groups to /etc/passwd via the GECOS field.

/bin/login in shadow 4.0.18.1 in Debian GNU/Linux, and probably other Linux distributions, allows local users in the utmp group to overwrite arbitrary files via a symlink attack on a temporary file referenced in a line (aka utline) field in a utmp entry.

The Debian installer for the (1) shadow 4.0.14 and (2) base-config 2.53.10 packages includes sensitive information in world-readable log files, including preseeded passwords and pppoeconf passwords, which might allow local users to gain privileges.