Microsoft Internet Explorer 6.0.2900.2180 and earlier allows remote attackers to cause a denial of service (CPU and memory consumption) via a long Unicode string argument to the write method, a related issue to CVE-2009-2479. NOTE: it was later reported that 7.0.6000.16473 and earlier are also affected.
Internet Explorer 5.1 for Macintosh allows remote attackers to bypass security checks and invoke local AppleScripts within a specific HTML element, aka the "Local Applescript Invocation" vulnerability.
Microsoft Internet Explorer 4.0 through 6.0 could allow local users to differentiate between alphanumeric and non-alphanumeric characters used in a password by pressing certain control keys that jump between non-alphanumeric characters, which makes it easier to conduct a brute-force password guessing attack.
Internet Explorer 4.x and 5.x does not properly verify all contents of an SSL certificate if a connection is made to the server via an image or a frame, aka one of two different "SSL Certificate Validation" vulnerabilities.
Internet Explorer 4.x and 5.x does not properly re-validate an SSL certificate if the user establishes a new SSL session with the same server during the same Internet Explorer session, aka one of two different "SSL Certificate Validation" vulnerabilities.
A Microsoft ActiveX control allows a remote attacker to execute a malicious cabinet file via an attachment and an embedded script in an HTML mail, aka the "Active Setup Control" vulnerability.