A remote overflow exists in ELM email clients prior to version 2.5.5. ELM fails to handle long 'message-id' headers resulting in a buffer overflow. With a specially crafted request, an attacker can cause other header fields and neigboring memory to overflow, resulting in a loss of integrity and/or availability.
Upgrade to version 2.5.5 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.