Several Cross Site Scripting vulnerabilities were discovered in SqWebmail. A remote attacker could exploit this to execute arbitrary JavaScript or other active HTML embeddable content in the web browser of an SqWebmail user by sending specially crafted emails to him.
Please note that the sqwebmail package is not officially supported by Ubuntu (it is in the universe section of the archive).
Solution: The problem can be corrected by upgrading the affected package to version 0.45.6-1ubuntu0.1 (for Ubuntu 4.10), or 0.47-3ubuntu1.3 (for Ubuntu 5.04). In general, a standard system upgrade is sufficient to effect the necessary changes.