CVE-2026-45659
Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run SharePoint Server, fix it now.
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.
US federal civilian agencies must remediate by Jul 4, 2026.
Patch status
No official fix confirmed yet
Until a fix ships, follow the vendor's mitigations and CISA's required action, limit exposure of affected systems, and watch this record for a patch.
Description
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Affected products
| Product | Vendor | Affected versions | Fixed in | Source |
|---|---|---|---|---|
| SharePoint Server | Microsoft | < 16.0.19725.20280; 2016; 2019 | 16.0.19725.20280 | KEV |
Sources: KEV = CISA Known Exploited Vulnerabilities catalog.
Intelligence timeline
Developments from the last 30 days, newest first.
No developments recorded for CVE-2026-45659 in the last 30 days.
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Coverage
We have not published a story about this vulnerability yet.