It was discovered that an internal Prosody library to load XML based on libexpat does not properly restrict the XML features allowed in parsed XML data. Given suitable attacker input, this results in expansion of recursive entity references from DTDs (CWE-776). In addition, depending on the libexpat version used, it may also allow injections using XML External Entity References (CWE-611).

An issue was discovered in Prosody before 0.11.9. It does not use a constant-time algorithm for comparing certain secret strings when running under Lua 5.2 or later. This can potentially be used in a timing attack to reveal the contents of secret strings to an attacker.

Prosody before 0.11.9 allows Uncontrolled CPU Consumption via a flood of SSL/TLS renegotiation requests.

An issue was discovered in Prosody before 0.11.9. Default settings are susceptible to remote unauthenticated denial-of-service (DoS) attacks via memory exhaustion when running under Lua 5.2 or Lua 5.3.

An issue was discovered in Prosody before 0.11.9. The proxy65 component allows open access by default, even if neither of the users has an XMPP account on the local server, allowing unrestricted use of the server's bandwidth.

prosody before versions 0.10.2, 0.9.14 is vulnerable to an Authentication Bypass. Prosody did not verify that the virtual host associated with a user session remained the same across stream restarts. A user may authenticate to XMPP host A and migrate their authenticated session to XMPP host B of the same Prosody instance.

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.

The generate_dialback function in the mod_dialback module in Prosody before 0.9.10 does not properly separate fields when generating dialback keys, which allows remote attackers to spoof XMPP network domains via a crafted stream id and domain name that is included in the target domain as a suffix.

The mod_dialback module in Prosody before 0.9.9 does not properly generate random values for the secret token for server-to-server dialback authentication, which makes it easier for attackers to spoof servers via a brute force attack.

Prosody before 0.9.4 does not properly restrict the processing of compressed XML elements, which allows remote attackers to cause a denial of service (resource consumption) via a crafted XMPP stream, aka an "xmppbomb" attack, related to core/portmanager.lua and util/xmppstream.lua.

plugins/mod_compression.lua in (1) Prosody before 0.9.4 and (2) Lightwitch Metronome through 3.4 negotiates stream compression while a session is unauthenticated, which allows remote attackers to cause a denial of service (resource consumption) via compressed XML elements in an XMPP stream, aka an "xmppbomb" attack.

Prosody before 0.8.1 does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.