A heap corruption exists in quassel version 0.12.4 in quasselcore that allows an attacker to execute code remotely (CVE-2018-1000178).
A NULL Pointer Dereference exists in quassel version 0.12.4 in the quasselcore that allows an atacker to denial of service by attempting a login when the database is not initialized (CVE-2018-1000179).
The Mageia 5 package has been patched to fix these issues and the Mageia 6 package has been upgraded to version 0.12.5, which also has other fixes and improvements.