Some vulnerabilities have been reported in SquirrelMail, which can be exploited by malicious people to conduct cross-site scripting, session fixation, and phishing attacks

1) Input passed via the URI is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

2) Input passed to contrib/decrypt_headers.php is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

3) An error in the handling of sessions can be exploited to hijack another user's session.

4) Input passed via emails is not properly sanitised before being displayed. This can be exploited to overlay GUI interface elements via CSS positioning when a specially crafted email is opened.

NOTE: It has also been reported that input passed to the example "map_yp_alias" username mapping function is not properly sanitised before being used in a shell command.

Solution
Update to version 1.4.19.

Provided and/or discovered by
The vendor credits:
1) Niels Teusink and Christian Balzer
2) Niels Teusink
3) Tomas Hoger
4) Luc Beurton

Changelog
Further details available in Customer Area

Original Advisory
http://www.squirrelmail.org/security/issue/2009-05-08
http://www.squirrelmail.org/security/issue/2009-05-09
http://www.squirrelmail.org/security/issue/2009-05-10
http://www.squirrelmail.org/security/issue/2009-05-11
http://www.squirrelmail.org/security/issue/2009-05-12

Deep Links
Links available in Customer Area