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.

The view-source CGI program allows remote attackers to read arbitrary files via a .. (dot dot) attack.

talkback in Netscape 4.5 allows a local user to overwrite arbitrary files of another user whose Netscape crashes.

talkback in Netscape 4.5 allows a local user to kill an arbitrary process of another user whose Netscape crashes.

The byte code verifier component of the Java Virtual Machine (JVM) allows remote execution through malicious web pages.

A configuration in a web browser such as Internet Explorer or Netscape Navigator allows execution of active content such as ActiveX, Java, Javascript, etc.

Buffer overflow in Netscape Communicator via EMBED tags in the pluginspage option.

When Javascript is embedded within the TITLE tag, Netscape Communicator allows a remote attacker to use the "about" protocol to gain access to browser information.

A remote attacker can read information from a Netscape user's cache via JavaScript.

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".

Buffer overflow in Netscape Communicator before 4.7 via a dynamic font whose length field is less than the size of the font.

Netscape Navigator uses weak encryption for storing a user's Netscape mail password.

Buffer overflow in Netscape Navigator/Communicator 4.7 for Windows 95 and Windows 98 allows remote attackers to cause a denial of service, and possibly execute arbitrary commands, via a long argument after the ? character in a URL that references an .asp, .cgi, .html, or .pl file.

Netscape Communicator 4.7 and earlier allows remote attackers to cause a denial of service, and possibly execute arbitrary commands, via a long certificate key.

Java in Netscape 4.5 does not properly restrict applets from connecting to other hosts besides the one from which the applet was loaded, which violates the Java security model and could allow remote attackers to conduct unauthorized activities.

Netscape Communicator 4.04 through 4.7 (and possibly other versions) in various UNIX operating systems converts the 0x8b character to a "<" sign, and the 0x9b character to a ">" sign, which could allow remote attackers to attack other clients via cross-site scripting (CSS) in CGI programs that do not filter these characters.

Netscape 4.7 records user passwords in the preferences.js file during an IMAP or POP session, even if the user has not enabled "remember passwords."

Netscape Mail Notification (nsnotify) utility in Netscape Communicator uses IMAP without SSL, even if the user has set a preference for Communicator to use an SSL connection, allowing a remote attacker to sniff usernames and passwords in plaintext.

security flaw

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.

Netscape 4.73 and earlier follows symlinks when it imports a new certificate, which allows local users to overwrite files of the user importing the certificate.