CVE-2026-62839 Microsoft CVE debrief

Who should care

Defenders responsible for SharePoint servers, security teams, and IT administrators should assess exposure and prioritize patching vulnerable instances.

Why it matters

Defenders should care about CVE-2026-62839 because it is a spoofing vulnerability in Microsoft SharePoint Server that could allow authorized attackers to perform spoofing over a network. The vulnerability affects multiple SharePoint Server versions and has a CVSS score of 6.5. Microsoft has released patches for this vulnerability, and defenders should prioritize patching vulnerable instances to prevent potential attacks.

• Potential spoofing attacks over the network.
• Need to verify and apply security patches.
• Monitoring SharePoint server logs for suspicious activity.

Technical summary

The vulnerability is caused by insufficiently protected credentials in Microsoft Office SharePoint, allowing an authorized attacker to perform spoofing over a network. The affected products are Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, and Microsoft SharePoint Server Subscription Edition.

Defensive priority

Defenders should prioritize patching vulnerable SharePoint servers to prevent potential spoofing attacks.

Recommended defensive actions

• Patch vulnerable Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, and Microsoft SharePoint Server Subscription Edition instances.
• Verify and apply the latest security updates from Microsoft.
• Monitor SharePoint server logs for potential spoofing attempts.

Evidence notes

The CVE record and source item provide details about the vulnerability, affected products, and vendor advisory. The vulnerability affects Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, and Microsoft SharePoint Server Subscription Edition. There are vendor advisories and patches available from Microsoft. Defenders should verify and apply security patches, and monitor SharePoint server logs for suspicious activity. The evidence is limited to publicly known

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.