Buffer overflow in (1) lprintf and (2) cprintf in sysdep.c of Citadel/UX 5.90 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via attacks such as a long HELO command to the SMTP server.

Format string vulnerability in the lprintf function in Citadel/UX 6.27 and earlier allows remote attackers to execute arbitrary code via format string specifiers sent to the server.

Buffer overflow in Citadel/UX 6.23 and earlier allows remote attackers to cause a denial of service via a long username.

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.

A Weak Session Management vulnerability in Citadel WebCit through 926 allows unauthenticated remote attackers to hijack recently logged-in users' sessions. NOTE: this was reported to the vendor in a publicly archived "Multiple Security Vulnerabilities in WebCit 926" thread.

Citadel WebCit through 926 allows unauthenticated remote attackers to enumerate valid users within the platform. NOTE: this was reported to the vendor in a publicly archived "Multiple Security Vulnerabilities in WebCit 926" thread.

Multiple cross-site scripting (XSS) vulnerabilities in Citadel WebCit through 926 allow remote attackers to inject arbitrary web script or HTML via multiple pages and parameters. NOTE: this was reported to the vendor in a publicly archived "Multiple Security Vulnerabilities in WebCit 926" thread.

An Insecure Direct Object Reference vulnerability in Citadel WebCit through 926 allows authenticated remote attackers to read someone else's emails via the msg_confirm_move template. NOTE: this was reported to the vendor in a publicly archived "Multiple Security Vulnerabilities in WebCit 926" thread.

An issue was discovered in Citadel through webcit-926. Meddler-in-the-middle attackers can pipeline commands after POP3 STLS, IMAP STARTTLS, or SMTP STARTTLS commands, injecting cleartext commands into an encrypted user session. This can lead to credential disclosure.

An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of "The STARTTLS command is only valid in non-authenticated state." in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.

A cross-site scripting vulnerability exists in Citadel versions prior to 994. When a malicious user sends an instant message with some JavaScript code, the script may be executed on the web browser of the victim user.