Microsoft Internet Explorer 5.01, 5.5 and 6.0 does not properly check the Cascading Style Sheet input parameter for Modal dialogs, which allows remote attackers to read files on the local system via a web page containing script that creates a dialog and then accesses the target files, aka "Modal Dialog script execution."

Buffer overflow in URLMON.DLL in Microsoft Internet Explorer 5.01, 5.5 and 6.0 allows remote attackers to execute arbitrary code via an HTTP response containing long values in (1) Content-type and (2) Content-encoding fields.

Microsoft Internet Explorer 5.5 and 6.0 allows remote attackers to bypass the cross-domain security model to run malicious script or arbitrary programs via dialog boxes, aka "Improper Cross Domain Security Validation with dialog box."

The showHelp() function in Microsoft Internet Explorer 5.01, 5.5, and 6.0 supports certain types of pluggable protocols that allow remote attackers to bypass the cross-domain security model and execute arbitrary code, aka "Improper Cross Domain Security Validation with ShowHelp functionality."

Microsoft Internet Explorer 6.0, when handling an expired CA-CERT in a webserver's certificate chain during a SSL/TLS handshake, does not prompt the user before searching for and finding a newer certificate, which may allow attackers to perform a man-in-the-middle attack. NOTE: it is not clear whether this poses a vulnerability.

Microsoft Internet Explorer 5.0 through 6.0 allows remote attackers to cause a denial of service (crash) via an object of type "text/html" with the DATA field that identifies the HTML document that contains the object, which may cause infinite recursion.

Internet Explorer 6.0 does not warn users when an expired certificate authority (CA) certificate is submitted to the user and a newer CA certificate is in the user's local repository, which could allow remote attackers to decrypt web sessions via a man-in-the-middle (MITM) attack.

Internet Explorer 5.5 and 6.0 allows remote attackers to bypass the cross-domain security model and access information on the local system or in other domains, and possibly execute code, via cached methods and objects, aka "Cross Domain Verification via Cached Methods."

Internet Explorer 5.01 through 6.0 does not properly perform security checks on certain encoded characters within a URL, which allows a remote attacker to steal potentially sensitive information from a user by redirecting the user to another site that has that information, aka "Encoded Characters Information Disclosure."

Internet Explorer 5.01 through 6.0 does not properly check certain parameters of a PNG file when opening it, which allows remote attackers to cause a denial of service (crash) by triggering a heap-based buffer overflow using invalid length codes during decompression, aka "Malformed PNG Image File Failure."