Jakob Balle discovered that with "Conditional Comments" in Internet Explorer it is possible to hide javascript code in comments that will be executed when the browser views a malicious email via sqwebmail. Successful exploitation requires that the user is using Internet Explorer.
For the old stable distribution (woody) this problem has been fixed in version 0.37.3-2.7.
For the stable distribution (sarge) this problem has been fixed in version 0.47-4sarge3.
For the unstable distribution (sid) this problem has been fixed in version 0.47-9.
We recommend that you upgrade your sqwebmail package.
MD5 checksums of the listed files are available in the original advisory.