Is CVE-2014-4123 (Microsoft Internet Explorer Privilege Escalation) being exploited in the wild?

What the KEV listing means for this CVE

CISA’s inclusion of CVE-2014-4123 in the Known Exploited Vulnerabilities catalog means you should treat this as an active exploitation issue, not just a historical Internet Explorer flaw. For defenders, the practical question is whether any legacy systems still expose the affected browser path and whether those systems can be reached from user browsing, email, or embedded web content.

Because the vulnerable component is a browser, exposure often extends beyond a single workstation image. Any environment that still permits the product, supports older compatibility modes, or depends on unsegmented legacy endpoints should assume a higher risk of exploitation pressure until the browser is removed, disabled, or isolated.

One useful reference point is CISA Known Exploited Vulnerabilities Catalog, which is the authoritative source for KEV inclusion and remediation expectations.

How organisations should confirm exposure and reduce attack surface

Start by identifying every system where Internet Explorer remains installed, enabled, or callable through compatibility settings, enterprise web applications, or legacy scripts. On many estates, the real risk is not the default browser choice but the residual path that still allows the vulnerable engine to execute when a user opens a crafted site or a trusted internal portal.

If you find the product still present, decide whether it can be removed, disabled, or prevented from handling untrusted web content. Where business dependencies remain, isolate those systems from routine browsing and restrict access to the narrowest set of users and sites required for the legacy workflow.

For broader prioritisation, the Zero-Day and Exploited Vulnerabilities Guide and Vulnerability Management Guide are useful when you need to turn KEV status into a remediation queue and exception process rather than handling this as a one-off browser issue.

What to do when patching or removal is delayed

If immediate removal is not possible, treat the system as temporarily high exposure and reduce the chance that a crafted site can reach it. Practical compensating controls include browser restriction, segmentation, limiting outbound web access from legacy hosts, and blocking unnecessary script and document handling paths that could invoke the vulnerable component.

Administrative access to any system that still depends on the vulnerable browser should be tightly bounded, because exploitation of a client-side privilege escalation flaw becomes more consequential when the same endpoint also has access to sensitive internal resources. Review local admin use, shared workstations, and remote support paths before assuming the browser issue is the only concern.

Legacy browser exceptions are easiest to justify when there is a clearly documented business requirement, a defined expiry date, and monitoring that shows whether the legacy path is still being used. Without those three elements, exceptions tend to outlive their original purpose and become permanent exposure.

Risk and Threat Considerations

This CVE matters because an exploited browser flaw can turn ordinary web activity into a privilege escalation path, which expands the attacker’s reach from user-level interaction to higher-value local access. In environments with older endpoints or weak segmentation, that can become a fast path to credential theft, lateral movement, or follow-on compromise.

Failure mechanism: A user loads a crafted web site in the affected browser, the vulnerability is triggered, and the attacker gains elevated privileges on the endpoint. From there, the attacker can abuse local trust, harvest data, or stage additional payloads from a system that was not supposed to grant that level of access.

Impact: Successful exploitation can expose sensitive browser-stored material, local secrets, and any internal applications reachable from the compromised host. In practice, the business impact is usually less about the browser itself and more about what the attacker can do once they control a trusted workstation.

Practitioner Guidance

What to verify: Confirm whether Internet Explorer is still installed, enabled, or reachable through compatibility settings on any production, administrative, or shared endpoint. Also verify whether those systems can reach sensitive internal resources that would increase the blast radius of a successful exploit.

Decision rule: If the browser is still present on a system that can access sensitive data or admin functions, prioritize removal or isolation over compensating controls alone. If business use must remain, document the exception, time-box it, and reduce the endpoint’s network and privilege scope.

Practitioner takeaway: For a KEV-listed browser flaw, the right question is not whether exploitation is theoretically possible, but whether any reachable legacy path still lets an attacker convert a web visit into higher-privilege access.

Related resources from NHI Mgmt Group

• Guide: Enterprise Browser and Browser Security Guide
• CVE-2014-4123 (Microsoft Internet Explorer Privilege Escalation)
• Is CVE-2014-1812 (Microsoft Windows Group Policy Preferences Password Privilege Escalation) being exploited in the wild?
• CVE-2014-2817 (Microsoft Internet Explorer Privilege Escalation)
• Is CVE-2021-31201 (Microsoft Enhanced Cryptographic Provider Privilege Escalation) being exploited in the wild?