The SASL negotiation in Jabber Studio jabberd before 2.0s11 allows remote attackers to cause a denial of service ("c2s segfault") by sending a "response stanza before an auth stanza".

Buffer overflow in the C2S module in the open source Jabber 2.x server (Jabberd) allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a long username.

The roster import functionality in Jabber Gadu-Gadu Transport (a.k.a. jabber-gg-transport) 2.0.x before 2.0.8, when using libgadu 1.0 and later, allows attackers to cause a denial of service via unknown vectors.

Jabber Gadu-Gadu Transport (a.k.a. jabber-gg-transport) 2.0.x before 2.0.8 allows remote attackers to cause a denial of service a message with an empty <priority/> tag.

Unknown vulnerability in Jabber Gadu-Gadu Transport (a.k.a. jabber-gg-transport) 2.0.x before 2.0.8 allows remote attackers to cause a denial of service (infinite loop) via user re-registration.

The expat XML parser code, as used in the open source Jabber (jabberd) 1.4.3 and earlier, jadc2s 0.9.0 and earlier, and possibly other packages, allows remote attackers to cause a denial of service (application crash) via a malformed packet to a socket that accepts XML connections.

jabber 1.4.2, 1.4.2a, and possibly earlier versions, does not properly handle SSL connections, which allows remote attackers to cause a denial of service (crash).