Summary
Impact: Spoofing. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software?
Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order.
I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running?
Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability.
What type of information could be disclosed by this vulnerability?
Exploiting this vulnerability could allow the disclosure of NetNTLMv2 hashes.
Security updates
16.0.5565.1001 — https://support.microsoft.com/help/5002905
16.0.5565.1001 — https://support.microsoft.com/help/5002906
16.0.10417.20198 — https://support.microsoft.com/help/5002894
16.0.10417.20198 — https://support.microsoft.com/help/5002896
16.0.19725.20522 — https://support.microsoft.com/help/5002893
Vulnerabilities 1
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Medium 6.5
Microsoft SharePoint Server Spoofing Vulnerability
Server-side request forgery (ssrf) in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
Revision history
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#1
Information published.
References
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CVE-2026-58639 Microsoft SharePoint Server Spoofing Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58639
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss