An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle...

Vulnerability Description

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.

References

• http://uncensored.citadel.org/dotgoto?room=Citadel%20Security
• https://uncensored.citadel.org/msg/2099264259
• https://nostarttls.secvuln.info/