PAM S/Key is a pluggable authentication module for the OpenBSD Single-key Password system.
Ulrich Müller reported that a Gentoo patch to PAM S/Key does not remove credentials provided by the user from memory.
A local attacker with privileged access could inspect a memory dump to gain access to cleartext credentials provided by users.
There is no known workaround at this time.
All PAM S/Key users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-auth/pam_skey-1.1.5-r5"