Motor.NET before 0.19.0 contains a denial of service vulnerability that allows a remote attacker who can publish to a consumed queue to crash the service permanently by sending a message with crafted cloudEvents headers. Attackers can supply an invalid cloudEvents:motorversion, a single double-quote header value, or an unparsable typed attribute such as cloudEvents:time to trigger an unhandled exception in ExtractCloudEvent that is treated as fatal, causing the application to stop and the unacknowledged message to be redelivered on restart, resulting in a permanent crash-loop.