Cybozu Garoon 2.x through 2.5.4 and 3.x through 3.7 SP3 does not properly manage sessions, which allows remote authenticated users to impersonate arbitrary users via unspecified vectors.
https://support.cybozu.com/ja-jp/article/7992
http://jvndb.jvn.jp/jvndb/JVNDB-2014-000021