It was discovered that incorrect SASL authentication in the Charybdis
IRC server may lead to users impersonating other users.
For the stable distribution (jessie), this problem has been fixed in
version 3.4.2-5+deb8u2.
For the unstable distribution (sid), this problem has been fixed in
version 3.5.3-1.
We recommend that you upgrade your charybdis packages.