CVE-2021-37845: Citadel Webcit

Low severity, CVSS 3.7. EPSS: 0.7% chance of exploitation in the next 30 days.

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.

Affected products

• Citadel Webcit: up to and including 932

Published 2023-05-29. Last modified 2026-06-17.