ImageMagick has a possible infinite loop in its JPEG encoder when using `jpeg:extent`

ImageMagick is free and open-source software used for editing and manipulating digital images. Prior to versions 7.1.2-15 and 6.9.13-40, a continue statement in the JPEG extent binary search loop in the jpeg encoder causes an infinite loop when writing persistently fails. An attacker can trigger a 100% CPU consumption and process hang (Denial of Service) with a crafted image. Versions 7.1.2-15 and 6.9.13-40 contain a patch.