An issue was discovered in Singularity 3.1.0 to 3.2.0-rc2, a malicious user with local/network access to the host system (e.g. ssh) could exploit this vulnerability due to insecure permissions allowing a user to edit files within `/run/singularity/instances/sing/<user>/<instance>`. The manipulation of those files can change the behavior of the starter-suid program when instances are joined resulting in potential privilege escalation on the host.
https://github.com/sylabs/singularity/releases/tag/v3.2.0
http://www.securityfocus.com/bid/108360
http://www.openwall.com/lists/oss-security/2019/05/16/1
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00059.html
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00028.html