Is CVE-2013-3897 (Microsoft Internet Explorer Use-After-Free) being exploited in the wild?

Yes. CISA added CVE-2013-3897 to its Known Exploited Vulnerabilities catalogue on 3 March 2022, which it does only when there is reliable evidence of active exploitation. CISA has not linked it to known ransomware campaigns. A use-after-free vulnerability exists within CDisplayPointer in Microsoft Internet Explorer that allows an attacker to remotely execute arbitrary code. Any organisation running the affected product should treat remediation as urgent.

What “Exploited in the Wild” Means for CVE-2013-3897

For a CVE like this, “being exploited in the wild” is operationally more important than the weakness label itself. CISA’s KEV inclusion means defenders should treat the issue as active, not theoretical, and prioritise exposure confirmation over debate about exploitability. The practical question is whether any Internet Explorer instances remain reachable in your environment and whether they can still be used to open untrusted content.

That is why remediation urgency should be tied to asset scope, not just patch status. If the product is still present on endpoints, VDI images, legacy kiosks, or compatibility hosts, the organisation should assume the attack surface is still live until those systems are removed, isolated, or otherwise made non-exploitable.

How to Confirm Exposure and Contain the Browser Surface

Start by identifying every system that can still run the affected browser component, including older Windows builds, unmanaged endpoints, and special-purpose workstations. Where the browser cannot be retired immediately, reduce exposure by restricting who can launch it, what sites it can reach, and whether it can access higher-value internal resources from the same session.

For browser-centric exposure, controls around policy enforcement, extension management, isolation, and credential protection matter because successful exploitation often turns a browsing session into code execution or follow-on theft. Enterprise Browser and Browser Security Guide is relevant here because it covers browser hardening, isolation, extension control, and credential theft paths that can magnify the impact of a browser exploit.

If a legacy browser must remain available for business reasons, the safer pattern is to constrain it to the smallest possible population and the least privileged network path. The goal is not to make an exploitable browser “safe,” but to prevent a successful exploit from immediately reaching sensitive data, privileged sessions, or administrative tools.

Patch, Triage, and Validate Before You Close the Ticket

Because CISA has placed the CVE in KEV, remediation should follow emergency vulnerability handling rather than normal backlog scheduling. Verify the vendor advisory and the KEV catalogue for the exact remediation path, then confirm that the fix actually landed on all in-scope assets instead of assuming a centralized patch job covered everything.

When patching is delayed, use compensating controls and document the exception tightly: isolate the affected browsers, limit outbound access, and monitor for suspicious child processes, crashes, or unusual browser launches. Vulnerability Management Guide is useful for prioritisation, verification, exceptions, and mean-time-to-remediate discipline, while Zero-Day and Exploited Vulnerabilities Guide covers the emergency response mindset that active exploitation demands.

After remediation, validate more than version numbers. Check for signs of pre-patch compromise, review endpoint telemetry for browser-based execution chains, and make sure any temporary workaround has been removed so the issue does not remain effectively exploitable through policy drift.

Risk and Threat Considerations

This CVE matters because a remotely exploitable browser memory corruption flaw can be used as an initial access path on systems that still trust browser activity as routine user behaviour. When a known exploited browser issue sits on a common desktop application, the attacker’s objective is often to gain execution with the user’s context and then pivot to data, credentials, or internal applications.

Failure mechanism: The vulnerability can allow malicious content to trigger use-after-free behaviour in the browser component, turning ordinary page rendering into arbitrary code execution on a reachable endpoint.

Impact: Successful exploitation can lead to endpoint compromise, session theft, malware deployment, and a wider foothold if the affected machine has access to sensitive services or privileged accounts.

Standards & Framework Alignment

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

NIST CSF 2.0, CIS Controls v8, NIST SP 800-53 Rev 5 and OWASP ASVS set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.

Framework	Control / Reference	Relevance
NIST CSF 2.0	ID.RA-01 — Asset Vulnerability Identification	Active exploitation depends on identifying exposed vulnerable assets.
	PR.PS-01 — Configuration Management	Browser hardening and isolation are configuration controls that reduce exploitability.
	DE.CM-01 — Networks and Functions Monitored	Post-exploitation browser abuse is best caught through continuous monitoring.
Recommendation — Identify systems still exposed to the vulnerable browser and track them for urgent remediation. Harden browser configurations and restrict legacy browser use to the smallest possible scope. Monitor browser execution, child processes, and unusual session activity for compromise signals.
CIS Controls v8	CIS-7 — Continuous Vulnerability Management	KEV-listed CVEs require urgent identification, prioritisation, and remediation tracking.
	CIS-4 — Secure Configuration of Enterprise Assets and Software	Browser isolation and policy restriction reduce reachable attack surface.
	CIS-8 — Audit Log Management	Incident hunting needs logs that can show suspicious browser-based execution chains.
Recommendation — Prioritise and remediate KEV-listed exposures before routine vulnerability backlog work. Apply restrictive browser configurations and remove unnecessary legacy browser access. Retain and review endpoint and browser logs for signs of exploit activity and follow-on execution.
NIST SP 800-53 Rev 5	SI-2 — Flaw Remediation	A KEV-listed CVE requires timely remediation and verification.
	CM-6 — Configuration Settings	Restricting the browser surface is a configuration-setting problem.
Recommendation — Remediate the vulnerability promptly and verify the fix across all in-scope assets. Lock down browser settings to reduce exposure and prevent unsafe legacy use.
ISO/IEC 27001:2022	A.8.8 — Management of technical vulnerabilities	The question is about actively exploited vulnerability handling and urgency.
Recommendation — Track, prioritise, and remediate exploited vulnerabilities through a formal vulnerability process.
OWASP ASVS	V13 — Configuration	Browser hardening and secure deployment settings are configuration concerns.
Recommendation — Use secure configuration controls to minimise exploitable browser exposure.

Practitioner Guidance

What to prioritise: Treat any remaining Internet Explorer exposure as a remediation item, not an advisory note. Prioritise systems that can browse the internet, open untrusted content, or access privileged internal resources from the same workstation.

What to verify: Confirm that the vulnerable component is actually absent or effectively unreachable, not just patched on paper. If a workaround is being used, verify that it cannot be bypassed by alternate launch paths, legacy shortcuts, or compatibility settings.

Practitioner takeaway: For an actively exploited browser CVE, the real control is rapid reduction of reachable exposure plus proof that the browser path is no longer usable for code execution or lateral movement.