CVE-2026-45659
highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.802 · 100 %ileexploit · PoCDEEURUUSadded 2026-07-01remediate by 2026-07-04
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.
EPSS · scored 2026-10-27
Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedMicrosoft SharePoint Enterprise Server 2016msrc_csaf
16.0.5552.1002:Security Update:https://support.microsoft.com/help/5002868
https://support.microsoft.com/help/5002868 - FixedMicrosoft SharePoint Server 2019msrc_csaf
16.0.10417.20128:Security Update:https://support.microsoft.com/help/5002870
https://support.microsoft.com/help/5002870 - FixedMicrosoft SharePoint Server Subscription Editionmsrc_csaf
16.0.19725.20280:Security Update:https://support.microsoft.com/help/5002863
https://support.microsoft.com/help/5002863
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
- HORKimhab/CVE-2026-45659CVE-2026-45659PoC · poc_in_github
affected products (21)
Products and version ranges known to be affected.
- microsoft sharepoint server< 16.0.19725.20280nvdUScpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:*:*:*:*
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1652Microsoft SharePoint Server 2016 und SharePoint Server 2019: Schwachstelle ermöglicht CodeausführungDeutsch2026-05-21csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in Microsoft SharePoint Server 2016, Microsoft SharePoint Server 2019 und Microsoft SharePoint ausnutzen, um beliebigen Programmcode auszuführen.
- msrc_CVE-2026-45659Microsoft SharePoint Remote Code Execution Vulnerability2026-05-21csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (4)
External citations — patches, advisories, analysis.
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659cnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659enisa_euvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659Vendor Advisorynvd
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45659US Government Resourcenvd
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