Live › vulnerability › CVE-2026-45659
Go to dashboardMicrosoft SharePoint Server has a deserialization of untrusted data flaw that lets an authorized attacker run code over the network. CISA lists it as actively exploited, with ransomware use noted in the tags.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| microsoft sharepoint server | vendor | < 16.0.19725.20280 | 16.0.19725.20280 |
| microsoft sharepoint server | vendor | = 2016 | – |
| microsoft sharepoint server | vendor | = 2019 | – |
| Microsoft SharePoint Server | vendor | – | – |
Identify SharePoint Server instances in your environment and confirm their build against Microsoft's security update guide for CVE-2026-45659; the sources do not give a specific build number or command.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.
CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
This page as .md · .json · in your agent: get_signal("CVE-2026-45659")
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