ACTIVELY EXPLOITED
CVE-2026-45659: Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability
| Vendor | Microsoft |
|---|---|
| Product | SharePoint Server |
| Actively exploited | Yes |
| Added to CISA KEV | 1 Jul 2026 |
| CISA federal deadline | 4 Jul 2026 |
| Ransomware use | Known |
| Weakness (CWE) | CWE-502 |
Required action (CISA's text)
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.
Description (NVD)
Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.
SOURCES
Other Microsoft flaws
- patchtuesday:2026-11: Vulnerability in Microsoft
- CVE-2026-124194: Microsoft Office Outlook Missing User Interaction for Potentially Unsafe Action Vulnerability
- CVE-2026-96951: Microsoft Windows Command Injection Vulnerability
- CVE-2026-65660: Microsoft SharePoint Code Injection Vulnerability
- CVE-2026-85880: Microsoft Windows Heap-Based Buffer Overflow Vulnerability
Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.