Cross-site scripting (XSS) vulnerability in index.html in IceWarp WebMail 5.5.1 and earlier allows remote attackers to inject arbitrary web script or HTML via the PHPSESSID parameter.

Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later packets because they appear to be too old.