Risk: Medium
A newfound flaw in Sendmail can permit attackers to launch Denial of Service attacks. The vulnerability occurs due to an error in the termination of the recursive "mime8to7()" function when performing MIME conversions. The flaw can then be exploited to cause a Sendmail process to crash when it runs out of stack space while processing a deeply nested malformed MIME message.
If the flaw is successfully exploited, it prevents queued messages from being delivered and can also fill up spare disk space with core dump files.
The vulnerability exists in versions 8.13.6 and prior; users are advised to upgrade to version 8.13.7, however, if that's not immediately available, Sendmail suggests three alternatives - install a nesting filter to block problematic messages, limit the size of incoming messages and change the queue run strategy.