Prosody before 0.10.0 allows remote attackers to cause a denial of service (application crash), related to an incompatibility with certain versions of the LuaSocket library, such as the lua-socket package from Debian stretch. The attacker needs to trigger a stream error. A crash can be observed in, for example, the c2s module.
Debian Linux Security Advisory 4198-1 - Albert Dengg discovered that incorrect parsing of <stream:error> messages in the Prosody Jabber/XMPP server may result in denial of service.