Opera before 10.00 does not check all intermediate X.509 certificates for revocation, which makes it easier for remote SSL servers to bypass validation of the certificate chain via a revoked certificate.

Opera before 10.00 trusts root X.509 certificates signed with the MD2 algorithm, which makes it easier for man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted server certificate.

Opera before 10.00 does not properly handle a (1) '\0' character or (2) invalid wildcard character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority.

Opera before 10.00 does not properly display all characters in Internationalized Domain Names (IDN) in the address bar, which allows remote attackers to spoof URLs and conduct phishing attacks, related to Unicode and Punycode.

Opera before 10.00 on Linux, Solaris, and FreeBSD does not properly implement the "INPUT TYPE=file" functionality, which allows remote attackers to trick a user into uploading an unintended file via vectors involving a "dropped file."

Opera before 10.00, when a collapsed address bar is used, does not properly update the domain name from the previously visited site to the currently visited site, which might allow remote attackers to spoof URLs.

Maxthon Browser 3.0.0.145 Alpha with Ultramode does not properly block javascript: and data: URIs in Refresh headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Refresh header that contains a javascript: URI, (2) entering a javascript: URI when specifying the content of a Refresh header, (3) injecting a Refresh header that contains JavaScript sequences in a data:text/html URI, or (4) entering a data:text/html URI with JavaScript sequences when specifying the content of a Refresh header; does not properly block data: URIs in Location headers in HTTP responses, which allows user-assisted remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (5) injecting a Location header that contains JavaScript sequences in a data:text/html URI or (6) entering a data:text/html URI with JavaScript sequences when specifying the content of a Location header; and does not properly hand…

Opera 9.52 and earlier, and 10.00 Beta 3 Build 1699, does not properly block data: URIs in Location headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Location header that contains JavaScript sequences in a data:text/html URI or (2) entering a data:text/html URI with JavaScript sequences when specifying the content of a Location header. NOTE: the JavaScript executes outside of the context of the HTTP site.

Orca Browser 1.2 build 5 does not properly block data: URIs in Refresh and Location headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Refresh header that contains JavaScript sequences in a data:text/html URI, (2) entering a data:text/html URI with JavaScript sequences when specifying the content of a Refresh header, (3) injecting a Location header that contains JavaScript sequences in a data:text/html URI, or (4) entering a data:text/html URI with JavaScript sequences when specifying the content of a Location header; and does not properly handle javascript: URIs in HTML links within 302 error documents sent from web servers, which allows user-assisted remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (5) injecting a Location HTTP response header or (6) specifying the content of a Location HTTP response header.

Maxthon Browser 2.5.3.80 UNICODE allows remote attackers to spoof the address bar, via window.open with a relative URI, to show an arbitrary URL on the web site visited by the victim, as demonstrated by a visit to an attacker-controlled web page, which triggers a spoofed login form for the site containing that page.