How do you patch or mitigate CVE-2022-26925 (Microsoft Windows LSA Spoofing)?

CISA’s required action for CVE-2022-26925 is to apply remediation actions outlined in CISA guidance [ In practice, find every instance of Microsoft Windows in your estate, apply the vendor security update or documented mitigation, and if no fix can be applied, remove internet exposure or take the product out of service. After patching, review logs for signs of earlier exploitation, because attackers used this flaw in the wild.

What patching looks like for an actively exploited Windows LSA spoofing flaw

The practical response is asset-wide, not instance-by-instance. Identify every Windows system that could carry the vulnerable component, apply the vendor security update or the documented mitigation, and treat unfixable systems as exposure to be removed from service or isolated from internet-facing paths. For actively exploited issues, the recovery step is part of the fix, not an optional follow-up.

For vulnerabilities being used in the wild, an emergency-response model is more appropriate than normal patch cadence. NHIMG’s Zero-Day and Exploited Vulnerabilities Guide covers the same operational pattern, triage, emergency mitigation, and post-patch hunting.

Use the vendor advisory and the CISA Known Exploited Vulnerabilities Catalog as the authoritative sources for the remediation requirement and timing, then align the rollout to your own asset criticality and outage tolerance.

How to mitigate when patching cannot happen immediately

If the security update is blocked by compatibility, maintenance windows, or system criticality, the next-best action is to reduce the attack surface until remediation is possible. That usually means removing direct internet exposure, tightening segmentation, and taking the affected product out of service where the business can tolerate it. Mitigation only buys time if the exposed path to exploitation is actually removed.

Where the vulnerable Windows estate is already difficult to enumerate, the first operational mistake is assuming a single patch bundle or baseline covers all variants. The Vulnerability Management Guide is useful here because it ties together asset scope, KEV triage, exceptions, and verification.

External references should do two jobs here: confirm exposure and confirm priority. The NIST National Vulnerability Database helps with record-level identification, while the KEV catalog tells you why this issue should be moved ahead of routine backlog items.

What to check after remediation

Once the patch or mitigation is in place, verify whether the environment was already touched before you close the case. For this class of flaw, that means reviewing authentication, privilege, and system logs for unusual activity that may indicate spoofing or follow-on abuse. The goal is to decide whether the issue was merely exposure or an actual compromise path.

This is where a short-lived technical fix can still leave a long-lived security problem. If attackers had a chance to use the flaw before remediation, you may need to inspect adjacent systems, not only the host that received the patch, because post-compromise movement often depends on the trust relationships exposed by the initial vulnerability.

For a broader view of how exploited vulnerabilities are handled across the lifecycle, the CVE Program is the canonical record source, and FIRST’s Exploit Prediction Scoring System is useful when you need to separate general severity from likely real-world exploitation pressure.

Risk and Threat Considerations

This type of Windows spoofing flaw matters because exploitation can turn a patching task into an identity and trust problem. If a hostile actor can abuse the flaw before remediation, the likely consequence is unauthorized access, impersonation, or a foothold that survives the initial patch unless you look for it explicitly.

Failure mechanism: The vulnerable component is abused to impersonate or confuse trusted Windows authentication flows, then the attacker uses the resulting access to pivot, persist, or harvest additional credentials and tokens.

Impact: You may be dealing with more than a vulnerable host, you may be dealing with a compromised trust boundary that requires log review, credential reset decisions, and containment beyond patching.

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 technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.

Framework	Control / Reference	Relevance
CIS Controls v8	CIS-7 — Continuous Vulnerability Management	Active exploitation makes vulnerability triage and remediation scheduling central.
Recommendation — Prioritise and verify remediation for exposed systems using a continuous vulnerability management process.
NIST CSF 2.0	DE.CM-09 — Vulnerability Monitoring	This CVE requires monitoring for vulnerable assets and signs of exploitation after remediation.
Recommendation — Monitor for vulnerable assets and exploitation indicators throughout the remediation window.
NIST SP 800-53 Rev 5	SI-2 — Flaw Remediation	The question is specifically about patching or mitigating a known software flaw.
	SI-4 — System Monitoring	Post-patch log review and compromise checking are part of handling an exploited CVE.
Recommendation — Apply flaw remediation quickly and document approved mitigations where patching is delayed. Review monitoring data for exploitation signs before closing remediation.
ISO/IEC 27001:2022	A.8.8 — Management of technical vulnerabilities	This page is about remediating a technical vulnerability using patching or mitigation.
Recommendation — Track, assess, and remediate technical vulnerabilities using a defined process.

Practitioner Guidance

What to prioritise: Patch the most exposed and highest-trust Windows systems first, especially anything internet reachable or used as a control point for other assets. If patching is delayed, remove the system from the path attackers would use, not just from the patch queue.

What to verify: Confirm that the vulnerable product really is absent or updated everywhere, then validate that the mitigation is operationally effective. If logs show suspicious access before remediation, treat the incident as a compromise assessment, not a normal patch ticket.

Practitioner takeaway: For actively exploited Windows flaws, the real question is not whether the patch is installed, but whether the environment was already used as an entry point and whether the trust relationships around it need to be reset.