functions/page_header.php in SquirrelMail 1.4.21 and earlier does not prevent page rendering inside a frame in a third-party HTML document, which makes it easier for remote attackers to conduct clickjacking attacks via a crafted web site.

References

• https://nvd.nist.gov/vuln/detail/CVE-2010-4554
• https://bugzilla.redhat.com/show_bug.cgi?id=720693
• https://exchange.xforce.ibmcloud.com/vulnerabilities/68512
• http://lists.apple.com/archives/security-announce/2012/Feb/msg00000.html
• http://rhn.redhat.com/errata/RHSA-2012-0103.html
• http://squirrelmail.svn.sourceforge.net/viewvc/squirrelmail/branches/SM-1_4-STABLE/squirrelmail/functions/page_header.php?view=patch&r1=14117&r2=14116&pathrev=14117
• http://support.apple.com/kb/HT5130
• http://www.debian.org/security/2011/dsa-2291
• http://www.mandriva.com/security/advisories?name=MDVSA-2011:123
• http://www.squirrelmail.org/security/issue/2011-07-12