CVE-2026-58644: Microsoft SharePoint remote code execution via untrusted deserialization

CVE-2026-58644 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2026-07-14

Microsoft SharePoint is a widely used collaboration and document management platform. A critical security flaw allows an unauthenticated attacker to remotely execute malicious code on the server over the network. This could lead to a total compromise of the server, including the theft of sensitive corporate data, service disruption, and a foothold for further attacks within the internal network.

Technologies: Microsoft SharePoint, Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, Microsoft SharePoint Server Subscription Edition. Vendors: Microsoft.

Quick answers

Is CVE-2026-58644 exploited in the wild?
Yes. CVE-2026-58644 is known to be exploited in the wild, first recorded on 16 July 2026. Treat it as urgent.
How severe is CVE-2026-58644?
Critical severity, with a CVSS score of 9.8, published 14 July 2026.
Which products and versions are affected?
Microsoft SharePoint Enterprise Server 2016 16.0.0 to < 16.0.5556.1005; Microsoft SharePoint Server 2019 16.0.0 to < 16.0.10417.20153; Microsoft SharePoint Server Subscription Edition 16.0.0 to < 16.0.19725.20384.
Is there a fix for CVE-2026-58644?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-58644 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-58644?
Check whether you run Microsoft SharePoint, Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A deserialization vulnerability (CWE-502) exists in Microsoft SharePoint due to the insecure handling of untrusted data. An unauthenticated attacker can exploit this by sending a specially crafted network request to an affected SharePoint server. Successful exploitation allows for remote code execution (RCE) in the context of the SharePoint service account. The vulnerability affects SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition. Microsoft has released security updates to address this issue; administrators should apply the latest patches for their respective versions.

Affected products

  • Microsoft SharePoint Enterprise Server 2016 16.0.0 to < 16.0.5556.1005
  • Microsoft SharePoint Server 2019 16.0.0 to < 16.0.10417.20153
  • Microsoft SharePoint Server Subscription Edition 16.0.0 to < 16.0.19725.20384

Timeline

  • 2026-07-14: disclosed: Initial disclosure by Microsoft Corporation
  • 2026-07-14: advisory: NVD record published
  • 2026-07-16: exploited: Reported as exploited in the wild per advisory metadata

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