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 before 4.77 allows remote attackers to execute arbitrary Javascript via a GIF image whose comment contains the Javascript.

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.

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.

Netscape Communicator 4.x allows attackers to use a link to steal a user's preferences, including potentially sensitive information such as URL history, e-mail address, and possibly the e-mail password, by redefining the userpref() function and accessing the prefs.js file, which is stored in a directory with a predictable name.

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.

Buffer overflow in Composer in Netscape 4.77 allows local users to overwrite process memory and execute arbitrary code via a font tag with a long face attribute.

Netscape 4.79 and earlier for MacOS allows an attacker with access to the browser to obtain passwords from form fields by printing the document into which the password has been typed, which is printed in cleartext.