CVE 2017-1000134
Mahara 1.8 before 1.8.6 and 1.9 before 1.9.4 and 1.10 before 1.10.1 and 15.04 before 15.04.0 are vulnerable because group members can lose access to the group files they uploaded if another group member changes the access permissions on them.
See the
CVE page on Mitre.org
for more details.