Is CVE-2025-49706 (Microsoft SharePoint Improper Authentication) being exploited in the wild?

By NHI Mgmt Group Editorial Team Updated October 19, 2026 Domain: Threats, Abuse & Incident Response

Yes. CISA added CVE-2025-49706 to its Known Exploited Vulnerabilities catalogue on 22 July 2025, which it does only when there is reliable evidence of active exploitation. CISA lists it as known to be used in ransomware campaigns. Microsoft SharePoint contains an improper authentication vulnerability that allows an authorized attacker to perform spoofing over a network.

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

For CVE-2025-49706, the practical question is not whether the flaw exists, but whether real attackers are already using it. CISA’s KEV listing is the strongest operational signal that exploitation is active, and it changes the response from routine patch planning to immediate exposure triage, emergency remediation, and post-compromise checking.

Because Microsoft SharePoint is the affected product and the weakness is improper authentication, the first task is to identify every internet-facing and internal SharePoint instance that could accept network-based authentication attempts. If you cannot confirm where SharePoint is exposed, you cannot judge blast radius or know which environments need urgent containment.

For guidance on prioritising exploited flaws, use the Zero-Day and Exploited Vulnerabilities Guide and the CISA Known Exploited Vulnerabilities Catalog as the authoritative starting points for exploitation-driven triage.

Why improper authentication on SharePoint is operationally serious

Improper authentication defects matter because they weaken the trust boundary before normal authorization checks can do their work. In a collaboration platform like SharePoint, that can expose content, application functions, or adjacent credentials and sessions, especially if the environment is already configured for broad internal access or connected to other Microsoft services.

The immediate security concern is not just direct unauthorized access, but what that access can enable next. Once an attacker can impersonate a legitimate user or bypass a trust check, they may move from information exposure into foothold creation, persistence, credential theft, or lateral movement into connected systems.

CISA’s KEV designation is a reminder to treat this as a live exploitation event, not a theoretical defect. If SharePoint is reachable from the internet or from untrusted network segments, the likelihood of opportunistic probing rises quickly after disclosure.

How to respond before and after patching

The right sequence is exposure confirmation, mitigation, patching, then compromise assessment. Start by inventorying all SharePoint servers, identifying which are externally reachable, and determining whether any compensating controls such as segmentation, access restrictions, or upstream filtering reduce exposure.

If patching must wait, reduce reachable attack surface immediately by restricting network access, tightening administrative paths, and disabling unnecessary exposure points around SharePoint. For a flaw tied to authentication, delay is dangerous when the service remains reachable because attackers do not need a user to click anything before they begin testing it.

After remediation, check for signs of earlier compromise rather than assuming the fix closes the entire incident. Review authentication logs, abnormal account creation or privilege changes, suspicious web activity, unexpected configuration changes, and any evidence that a valid session or token was issued before containment.

Where SharePoint credentials, sessions, or service-side secrets may have been exposed, rotate them as part of the response. If the environment uses linked service accounts, application credentials, or keys for integrations, review those too, because exploitation of a front-door authentication issue can create a broader trust problem than the CVE title alone suggests.

Risk and Threat Considerations

When authentication flaws are actively exploited, the main risk is not only unauthorized entry, but silent abuse of a trusted business platform before defenders notice unusual behaviour. SharePoint often sits close to sensitive documents, internal workflows, and identity-linked access paths, so a compromise can create both confidentiality loss and follow-on movement risk.

Failure mechanism: An attacker probes the exposed SharePoint service, bypasses or abuses the improper authentication condition, and uses that access to reach content or trigger additional post-authentication abuse before the team has time to detect the pattern.

Impact: The result can include unauthorized access to documents, credential or session exposure, deeper lateral movement, and ransomware-relevant footholds if the compromised platform is part of the path into broader internal systems.

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 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 CVEs require fast exposure triage and remediation prioritization.
Recommendation — Prioritize and remediate KEV-listed SharePoint exposure immediately.
NIST SP 800-53 Rev 5	RA-5 — Vulnerability Monitoring and Scanning	The question centers on confirming exploitable exposure and tracking known vulnerabilities.
	SI-2 — Flaw Remediation	Active exploitation makes prompt remediation and exception handling essential.
	AU-6 — Audit Record Review, Analysis, and Reporting	Post-compromise review of authentication and activity logs is central after exploitation.
Recommendation — Scan SharePoint assets and track this CVE as a high-priority finding. Apply the vendor fix or approved mitigation without delay. Review logs for authentication abuse and suspicious post-login activity.
NIST CSF 2.0	ID.RA-01 — Asset Vulnerability Identification	Exploit confirmation depends on identifying vulnerable SharePoint assets and exposure paths.
Recommendation — Identify every SharePoint instance and its exposure path before triaging risk.

Practitioner Guidance

What to prioritise: Treat CISA KEV listing as a “fix first” trigger, then confirm which SharePoint hosts are internet-facing, which business units rely on them, and which environments would be most damaging if compromised.

What to verify: Validate whether logging is sufficient to reconstruct authentication attempts, successful logins, and post-authentication actions. If you cannot distinguish normal access from suspicious access, incident response will be slower and less reliable.

Decision rule: If SharePoint is exposed and patching is not yet complete, assume exploit attempts are already underway and apply compensating containment immediately rather than waiting for proof of exploitation in your own environment.

Practitioner takeaway: For KEV-listed authentication flaws, the operational question is not “is this patch available?”, but “can we prove exposure, contain it quickly, and determine whether the platform was already used as an entry point?”

Deepen Your Knowledge

Free weekly newsletter

Subscribe to the NHI & AI Identity Journal

The latest on NHI and Agentic AI security – articles, research, breaches, news and events every week.

Bonus 33% off our NHI Course when you subscribe.

NHIMG Editorial Note
Reviewed and updated by the NHIMG editorial team on October 19, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org