Netscape 4.75 HTML Parser Buffer Overflow
Severe, but no confirmed exploitation yet. Schedule remediation in your next patch cycle and apply mitigations if you're exposed.
An unauthenticated attacker, remotely over the network, can cause limited impact to confidentiality and integrity and availability.
Buffer overflow in the HTML parser for Netscape 4.75 and earlier allows remote attackers to execute arbitrary commands via a long password value in a form field.
Inferred from the weakness type (CWE) and how the flaw is reached — the techniques an attacker would chain to exploit this. Real-world corroboration appears here as threat intel is folded in.
Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.
Implement network-level filtering to block or restrict access to untrusted web content for systems still running Netscape 4.75. Advise users to avoid browsing unverified or suspicious websites with this outdated browser. Consider deploying a more secure, modern browser for general web usage to minimize exposure.
The permanent fix involves discontinuing the use of Netscape Navigator 4.75 and earlier versions immediately. Users should upgrade to a modern, supported web browser that has received security updates, as Netscape 4.x is end-of-life and will not receive further patches for this vulnerability. Replacing the vulnerable software is crucial to eliminate the risk of arbitrary code execution.
Attackers can exploit this buffer overflow by sending a crafted HTML form with an excessively long password value. Successful exploitation enables arbitrary code execution on the victim's machine, leading to complete system compromise, data theft, or further network penetration. This poses a significant risk of data breaches, operational disruption, and reputational damage.
No CWE classification has been assigned.
Other CVEs affecting communicator
Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.
It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.
Netscape Communicator before 4.77 allows remote attackers to execute arbitrary Javascript via a GIF image whose comment contains the Javascript.
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.
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 4.04 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.