HTTP response splitting vulnerability in index.php in phpSysInfo 2.4 and earlier, as used in phpgroupware 0.9.16 and earlier, and egroupware before 1.0.0.009, allows remote attackers to spoof web content and poison web caches via CRLF sequences in the charset parameter.
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.