CVE-2011-1756: Citadel

Medium severity, CVSS 5.0. EPSS: 2.7% chance of exploitation in the next 30 days.

modules/xmpp/serv_xmpp.c in Citadel 7.86 and earlier 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.

Affected products

• Citadel Citadel: up to and including 7.86; version 7.11 only; version 7.50 only; version 7.60 only; version 7.80 only; version 7.81 only; …

Published 2011-06-21. Last modified 2026-06-16.