Buffer overflow in the sun.awt.windows.WDefaultFontCharset Java class implementation in Netscape 4.0 allows remote attackers to execute arbitrary code via an applet that calls the WDefaultFontCharset constructor with a long string and invokes the canConvert method.
Netscape Communicator does not properly prevent a ServerSocket object from being created by untrusted entities, which allows remote attackers to create a server on the victim's system via a malicious applet, as demonstrated by Brown Orifice.
The view-source CGI program allows remote attackers to read arbitrary files via a .. (dot dot) attack.
Netscape Communicator 4.0 through 4.79 allows remote attackers to bypass JVM security and execute arbitrary Java code via an applet that loads user-supplied Java classes.
Netscape Communicator and Navigator 4.04 through 4.74 allows remote attackers to read arbitrary files by using a Java applet to open a connection to a URL using the "file", "http", "https", and "ftp" protocols, as demonstrated by Brown Orifice.
Netscape Communicator 4.73 and earlier allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.
Netscape 4.73 and earlier does not properly warn users about a potentially invalid certificate if the user has previously accepted the certificate for a different web site, which could allow remote attackers to spoof a legitimate web site by compromising that site's DNS information.
Netscape Communicator 4.x with Javascript enabled does not warn a user of cookie settings, even if they have selected the option to "Only accept cookies originating from the same server as the page being viewed".
The POP3 mail client in Mozilla 1.0 and earlier, and Netscape Communicator 4.7 and earlier, allows remote attackers to cause a denial of service (no new mail) via a mail message containing a dot (.) at a newline, which is interpreted as the end of the message.
Mozilla 0.9.6 and earlier and Netscape 6.2 and earlier allows remote attackers to steal cookies from another domain via a link with a hex-encoded null character (%00) followed by the target domain.
Netscape Communicator before version 4.73 and Navigator 4.07 do not properly validate SSL certificates, which allows remote attackers to steal information by redirecting traffic from a legitimate web server to their own malicious server, aka the "Acros-Suencksen SSL" vulnerability.
A remote attacker can read information from a Netscape user's cache via JavaScript.
JavaScript in Internet Explorer 3.x and 4.x, and Netscape 2.x, 3.x and 4.x, allows remote attackers to monitor a user's web activities, aka the Bell Labs vulnerability.