Is CVE-2015-2425 (Microsoft Internet Explorer Memory Corruption) being exploited in the wild?

Yes. CISA added CVE-2015-2425 to its Known Exploited Vulnerabilities catalogue on 25 May 2022, which it does only when there is reliable evidence of active exploitation. CISA has not linked it to known ransomware campaigns. Microsoft Internet Explorer contains a memory corruption vulnerability that allows remote attackers to execute code or cause denial-of-service (DoS). Any organisation running the affected product should treat remediation as urgent.

Why the “Exploited in the Wild” Answer Matters for CVE-2015-2425

This is not just a patch-status question. When a CVE is in CISA’s KEV catalogue, the operational assumption should be that exploit activity is already credible enough to warrant priority action, even if your own telemetry has not yet flagged abuse. For internet explorer memory corruption, the practical concern is code execution on a widely exposed client application, which can turn ordinary browsing into an entry path.

Because the direct answer already confirms active exploitation, the issue should be handled as an urgent exposure review rather than a theoretical vulnerability assessment. The first decision is whether any systems still depend on the affected product, and whether those systems are reachable by users, third-party content, or legacy workflows that can still trigger the browser.

For a browser-class vulnerability, confirmation is not limited to whether Internet Explorer is your preferred browser. Legacy components, compatibility modes, embedded web rendering, and old enterprise images can keep the attack surface alive long after the application is no longer in daily use. The right question is whether the vulnerable code path can still execute anywhere in the environment.

What Practitioners Should Check First

Start with exposure confirmation: identify hosts where the affected Microsoft Internet Explorer components remain installed, enabled, or callable. Then determine whether those systems are internet-facing, used for email or web access, or exposed to untrusted content, because those conditions materially increase exploitation likelihood and impact.

The practical remediation path is to follow the vendor advisory and the CISA KEV catalogue for exact version and patch instructions, then remove or disable the vulnerable browser path wherever possible. For an actively exploited client-side flaw, the safest response is usually to reduce reachability as much as patching, especially if the affected software persists only for compatibility.

If patching must wait, treat containment as temporary risk reduction, not as a fix. Limit the affected systems’ access to untrusted web content, constrain who can use them, and monitor for suspicious script execution, child processes, or unusual browser-driven activity that could indicate exploitation or follow-on payload delivery.

What Evidence of Compromise Is Worth Looking For

Memory corruption flaws often leave indirect signs rather than a clean alert. Investigators should review endpoint telemetry, browser and process launch chains, and any sudden changes in accounts, persistence, or downloaded files after web activity. A successful exploit may be followed by additional payload staging, so compromise review should extend beyond the browser itself.

If the vulnerable system was used with privileged credentials, or if it handled access to sensitive internal applications, review whether the compromise could have exposed sessions, cached secrets, or internal trust relationships. That step matters most where the browser was a bridge into administrative or business-critical resources.

Risk and Threat Considerations

Actively exploited browser vulnerabilities are attractive because they combine a user-driven entry point with code execution on an endpoint that often has access to internal systems, saved sessions, and sensitive content. Even without ransomware linkage, the likely consequence is unauthorized execution, payload delivery, and downstream compromise of the workstation or the user context.

Failure mechanism: An attacker can induce the vulnerable IE memory corruption through malicious content or a booby-trapped page, then use the resulting execution to stage additional malware, steal data, or move further into the environment.

Impact: The organisation may face endpoint compromise, credential or session exposure, lateral movement, and business disruption, especially if the affected browser path is still enabled on machines that users trust for routine work.

Standards & Framework Alignment

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

CIS Controls v8, NIST SP 800-53 Rev 5, NIST CSF 2.0 and OWASP ASVS set the governance and control requirements practitioners need to meet.

Framework	Control / Reference	Relevance
CIS Controls v8	CIS-7 — Continuous Vulnerability Management	Prioritises rapid handling of KEV-listed, actively exploited software flaws.
Recommendation — Triage KEV-listed exposure first and accelerate remediation for affected assets.
NIST SP 800-53 Rev 5	SI-2 — Flaw Remediation	Requires timely remediation of a known exploited vulnerability on endpoints.
	AU-6 — Audit Review, Analysis, and Reporting	Supports investigation of exploit traces and suspicious browser activity after exposure.
Recommendation — Apply SI-2 to remediate the vulnerable browser path as soon as feasible. Review endpoint and browser telemetry for signs of exploitation and follow-on activity.
NIST CSF 2.0	ID.RA-01 — Asset Vulnerabilities Are Identified and Recorded	The answer depends on identifying where the vulnerable browser still exists.
Recommendation — Identify exposed systems and record where the vulnerable product remains present.
OWASP ASVS	V12 — Secure Communication	Browser exploitation often begins through malicious content delivery and trust in web traffic.
Recommendation — Harden browser-facing paths that process untrusted content and web traffic.

Practitioner Guidance

What to prioritise: Prioritise systems where the affected browser path is still reachable and where a successful exploit would land on a privileged or business-critical user context. A legacy browser that remains installed but unused is lower risk than one that can still process untrusted web content on active endpoints.

What to verify: Verify both the presence of the vulnerable software and the business reason it still exists. If the answer is compatibility, test whether that dependency can be isolated, disabled, or replaced without preserving the attack surface.

Practitioner takeaway: For an actively exploited browser CVE, the operational goal is to shrink exposure fast, then prove that the vulnerable path is gone, not merely patched on paper.