When adding an external mail account, processing of IMAP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue IMAP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted IMAP server response to reasonable length/size. No publicly available exploits are known.
Publication date: Tue, 20 Jun 2023 13:15:00 +0000