It was found that libpam4j up to and including 1.8 did not properly validate user accounts when authenticating. A user with a valid password for a disabled account would be able to bypass security restrictions and possibly access sensitive information.
https://www.debian.org/security/2017/dsa-4025
https://lists.debian.org/debian-lts-announce/2017/11/msg00008.html
https://bugzilla.redhat.com/show_bug.cgi?id=1503103
https://access.redhat.com/errata/RHSA-2017:2906