Is CVE-2019-0752 (Microsoft Internet Explorer Type Confusion) being exploited in the wild?

Yes. CISA added CVE-2019-0752 to its Known Exploited Vulnerabilities catalogue on 15 February 2022, which it does only when there is reliable evidence of active exploitation. CISA lists it as known to be used in ransomware campaigns. A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer

What “exploited in the wild” means for this CVE

For a browser vulnerability like CVE-2019-0752, “exploited in the wild” means more than proof-of-concept code or theoretical impact. It means defenders should assume real attack traffic has existed, exposure may already be widespread, and the issue belongs in active prioritisation rather than normal backlog handling. CISA’s KEV listing is the operational signal that matters most for that call.

The practical question is not whether the flaw is interesting, but whether any Internet Explorer exposure remains on the estate and whether the vulnerable scripting engine path is still reachable. If the browser or the embedded rendering engine is still present, the risk is no longer abstract, especially because browser exploitation often precedes foothold, payload delivery, and follow-on credential theft.

How to confirm whether you are exposed

Start by identifying every system that can still invoke Internet Explorer, including legacy compatibility modes, embedded components, and unmanaged endpoints that may not be covered by modern browser policy. In many environments the real exposure is not “people use IE as their main browser,” but that the engine still exists for a small set of legacy workflows.

Check whether enterprise browser controls, application compatibility settings, or old intranet dependencies keep the code path alive. NHIMG’s Enterprise Browser and Browser Security Guide is a useful companion when you need to inventory browser features, extension risk, and policy-based hardening in the same review.

For security teams, the best confirmation is endpoint scope plus attack surface, not user reporting. If the affected engine is enabled on even a small number of systems, treat those hosts as priority candidates for patching, containment, and log review because browser exploitation tends to be opportunistic once a working chain exists.

What to do when patching is delayed or the risk is still active

If patching or removal cannot happen immediately, reduce reachable exposure first: restrict browser use to the minimum necessary population, remove legacy browser access where possible, and tighten web filtering and attack-surface controls around the endpoints that still need it. The goal is to shrink the number of systems that can be reached through the vulnerable path, not to rely on users noticing malicious content.

Use CISA KEV as the operational priority source, then validate vendor guidance for the exact remediation path rather than trying to infer it from the CVE name alone. CISA Known Exploited Vulnerabilities Catalog is the right place to confirm the exploitation status and required action, while the vendor advisory should drive the specific fix sequence.

If you need a broader prioritisation model for active exploitation, Zero-Day and Exploited Vulnerabilities Guide helps structure emergency triage, temporary mitigation, and post-fix validation for vulnerabilities that have moved from theoretical to operational risk.

What else to check after remediation

Once remediation is complete, review whether the vulnerable browser path was used as an initial access vector. Browser exploitation can leave little direct evidence unless telemetry is already tuned for unusual process launches, script abuse, suspicious child processes, or strange outbound connections from user workstations.

Look for signs of post-exploitation activity on the same endpoints, especially credential theft, suspicious persistence, or unusual authentication events shortly after the time window in which the vulnerable browser was exposed. If a device was reachable and unpatched while the issue was actively exploited, treat compromise assessment as a normal part of closure, not an exceptional step.

Risk and Threat Considerations

This CVE matters because browser exploitation is often a low-friction entry point into broader compromise. A remotely reachable code execution flaw in a widely deployed browser engine can be used to deliver a foothold without any prior trust relationship, then pivot into payload staging, user data access, or downstream credential capture.

Failure mechanism: An attacker delivers crafted content that abuses the scripting engine’s memory handling, triggers code execution in the browser process, and uses that execution to launch follow-on activity on the endpoint.

Impact: The immediate outcome may be workstation compromise, but the larger risk is lateral movement, credential theft, and secondary malware deployment, including ransomware activity where the compromised host becomes an entry point rather than the final target.

Standards & Framework Alignment

This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.

CIS Controls v8 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.

Framework	Control / Reference	Relevance
CIS Controls v8	CIS-7 — Continuous Vulnerability Management	Actively exploited vulnerabilities require prioritised remediation and exposure tracking.
	CIS-4 — Secure Configuration of Enterprise Assets and Software	Legacy browser components and compatibility settings create avoidable exposure.
Recommendation — Prioritise this CVE for rapid remediation and verify remediation coverage across all exposed systems. Disable or remove legacy browser paths and enforce hardened endpoint configurations.
NIST CSF 2.0	ID.RA-01 — Asset Vulnerability Identified	Exposure depends on discovering where the vulnerable browser path still exists.
	PR.PS-01 — Configuration Management	Reducing the reachable attack surface depends on configuration and legacy feature control.
	DE.CM-01 — Networks and network services are monitored to detect potential cybersecurity events	Post-exploitation review depends on telemetry that can reveal browser-driven compromise.
Recommendation — Inventory endpoints that can still invoke the vulnerable browser engine and rank them for urgent action. Restrict or eliminate legacy browser functionality through managed configuration. Monitor endpoint and network telemetry for suspicious activity following remediation.

Practitioner Guidance

What to prioritise: Treat any still-exposed Internet Explorer capability as a high-priority exception until you can prove it is removed or isolated. In practice, that means identifying the systems that can still invoke the engine, not just the users who prefer older workflows.

What to verify: Confirm that remediation actually removes the reachable attack path, then validate with endpoint telemetry that no legacy dependency silently re-enables it. If you cannot prove the path is gone, assume the exposure remains operational.

Practitioner takeaway: For a KEV-listed browser flaw, the important decision is not whether the exploit is clever, but whether any reachable legacy browser surface remains in production and therefore still deserves emergency treatment.