Stalwart is a mail and collaboration server. A denial-of-service vulnerability exists in Stalwart Mail Server versions 0.13.0 through 0.15.4 where accessing a specially crafted email containing malformed nested message/rfc822 MIME parts via IMAP or JMAP causes excessive CPU and memory consumption, potentially leading to an out-of-memory condition and server crash. The malformed structure causes the mail-parser crate to produce cyclical references in its parsed representation, which Stalwart then follows indefinitely. Version 0.15.5 contains a patch.

Stalwart Mail Server is an open-source mail server. Prior to version 0.8.0, attackers who achieved Arbitrary Code Execution as the stalwart-mail user (including web interface admins) can gain complete root access to the system. Usually, system services are run as a separate user (not as root) to isolate an attacker with Arbitrary Code Execution to the current service. Therefore, other system services and the system itself remains protected in case of a successful attack. stalwart-mail runs as a separate user, but it can give itself full privileges again in a simple way, so this protection is practically ineffective. Server admins who handed out the admin credentials to the mail server, but didn't want to hand out complete root access to the system, as well as any attacked user when the attackers gained Arbitrary Code Execution using another vulnerability, may be vulnerable. Version 0.8.0 contains a patch for the issue.

Stalwart Mail Server is an open-source mail server. Prior to version 0.8.0, when using RUNASUSER, the specified user (and therefore, web interface admins) can read arbitrary files as root. This issue affects admins who have set up to run stalwart with RUNASUSER who handed out admin credentials to the mail server but expect these to only grant access according to the RUNASUSER and are attacked where the attackers managed to achieve Arbitrary Code Execution using another vulnerability. Version 0.8.0 contains a patch for the issue.