Is CVE-2016-0151 (Microsoft Windows CSRSS Security Feature Bypass) being exploited in the wild?

Yes. CISA added CVE-2016-0151 to its Known Exploited Vulnerabilities catalogue on 28 March 2022, which it does only when there is reliable evidence of active exploitation. CISA lists it as known to be used in ransomware campaigns. The Client-Server Run-time Subsystem (CSRSS) in Microsoft mismanages process tokens, which allows local users to gain privileges via a crafted application.

What “being exploited in the wild” means for this CVE

This question is less about the defect itself and more about whether defenders should treat it as an active incident-response item. For CVE-2016-0151, the practical answer is yes: it has entered the category of vulnerabilities where exposure can be turning into compromise, not just theoretical risk. That changes prioritisation, verification urgency, and how much confidence you can place in “we will patch later”.

Because CISA only adds a vulnerability to the Known Exploited Vulnerabilities catalogue when it has reliable evidence of active exploitation, the operational assumption should be that adversaries have already found ways to reach it. That makes the question a triage problem, not a research question.

What to do if Windows CSRSS exposure is still present

The first step is to confirm whether any Windows systems in scope can still execute the vulnerable CSRSS path. In practice, that means identifying endpoints, VDI hosts, kiosks, legacy servers and any environment that has not been aligned to the current vendor guidance. When a local privilege bypass is publicly known and listed in KEV, patching or mitigation should be treated as a priority control, not as a routine backlog item.

If you need a broader response playbook for active exploitation, the Zero-Day and Exploited Vulnerabilities Guide is the best internal starting point for KEV triage, emergency mitigation and post-patch hunting. For inventory-driven remediation, pair that with the Vulnerability Management Guide, which helps turn “known exploited” into a concrete remediation queue.

If patching has to wait, the compensating control is to reduce the opportunity for local exploitation and tighten monitoring around privilege changes. That usually means limiting interactive use on exposed systems, reviewing who can log on locally, and checking whether any administrative activity coincides with the time the vulnerability may have been reachable.

How to check for earlier compromise and likely follow-on abuse

Once a vulnerability is known to be exploited in the wild, the next question is whether it was used before remediation. The most useful checks are local privilege escalation indicators, unexpected new administrative access, suspicious process creation around the CSRSS-related path, and any account changes that do not match normal operations. Do not stop at the vulnerable host itself if the system had access to sensitive shares, management planes or service credentials.

On Windows estates, the Windows Event Log Guide is a practical reference for the event types that matter when you are testing for privilege escalation and post-exploitation activity. If your environment is broadly Windows-based, the Windows Endpoint Hardening Guide is useful for understanding which protections should already be in place to blunt local privilege abuse.

For a public authority view of the exact vulnerability record and exploitation status, confirm the entry in the CISA Known Exploited Vulnerabilities Catalog and cross-check the record in the CVE Program. If you need product and record context, the NIST National Vulnerability Database is the standard reference point.

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 CSF 2.0 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.

Framework	Control / Reference	Relevance
CIS Controls v8	CIS-7 — Continuous Vulnerability Management	Active exploitation makes prioritized remediation and verification essential.
Recommendation — Prioritise remediation of KEV-listed Windows systems and verify exposure is removed.
NIST CSF 2.0	DE.CM-01 — Networks and network services are monitored to find potentially adverse events	Exploited-in-the-wild flaws require monitoring for signs of compromise and abuse.
Recommendation — Monitor affected Windows hosts for privilege-escalation and post-exploitation indicators.
NIST SP 800-53 Rev 5	RA-5 — Vulnerability Monitoring and Scanning	The question is about identifying and acting on an actively exploited vulnerability.
	AU-6 — Audit Record Review, Analysis, and Reporting	Checking for prior compromise depends on reviewing logs for suspicious elevation or persistence.
	AC-6 — Least Privilege	A local privilege-bypass flaw is less damaging when systems and users are not overprivileged.
Recommendation — Continuously scan and track affected assets, then drive rapid remediation for the exposed CVE. Review audit records for suspicious logons, process creation and privilege changes around the exposure window. Reduce local administrative access and constrain privilege paths that the flaw could abuse.

Practitioner Guidance

What to prioritise: Treat this as a privilege-escalation exposure with confirmed exploitation, so prioritise affected Windows assets that are internet-adjacent, operationally critical, or frequently used by administrative staff. If you have to sequence work, start with systems that could turn local elevation into broader domain or management-plane access.

What to verify: Verify not only that remediation is applied, but that the host has not already shown signs of abuse before the fix. A clean patch state does not rule out prior compromise, especially where the attacker’s goal would have been credential capture, persistence or lateral movement after gaining elevated rights.

What good looks like: The vulnerable build is removed or mitigated, local administrative paths are reduced, and logging is sufficient to explain whether suspicious elevation occurred. If you cannot explain privilege changes from available telemetry, treat the system as needing deeper investigation rather than merely a standard patch confirmation.

Practitioner takeaway: Once KEV confirms active exploitation, the decision shifts from “should we patch?” to “how quickly can we contain exposure and prove the host was not already abused?”