Michael Marek discovered that the Horde web application framework performs insufficient input sanitising, which might lead to the injection of web script code through cross-site scripting.
The old stable distribution (woody) does not contain horde3 packages.
For the stable distribution (sarge) this problem has been fixed in version 3.0.4-4sarge4.
For the unstable distribution (sid) this problem has been fixed in version 3.1.1-3.
We recommend that you upgrade your horde3 package.
MD5 checksums of the listed files are available in the original advisory.