Summary
| Parameter | Value |
|---|---|
| CVE ID | CVE-2026-45659 |
| Alert Source | CISA KEV - Active Exploitation |
| CVE Publication Year | 2026 |
| Date Published | 2026-07-01 |
| Vendor | Microsoft |
| Product | SharePoint Server |
| CVSS Score | 8.8 (high) |
| EPSS Score | 2.8% (percentile: 85%) |
| CISA KEV | Yes - confirmed active exploitation |
| Ransomware | Not confirmed |
| Remediation Deadline | 2026-07-04 |
Vulnerability Description
Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.
Required Actions
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.
Who Is Affected?
This vulnerability affects SharePoint Server by Microsoft. Check if your organization uses this software and requires updates.
Sources
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