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Vulnerabilities / CVE-2026-45659

CVE-2026-45659

Published 2026-05-22 · Analyzed

CVE-2026-45659

Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability

Exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-07-01, with a fix-by date of 2026-07-04. Patch it first.

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.

8.8 HIGH
CVSS 3.1 · CNA · microsoft.com
80%
chance of exploitation in the next 30 days (EPSS; in the top 1% of all CVEs)

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

Scores

Affected products

  • microsoft sharepoint server: < 16.0.19725.20280; 2016; 2019

Weakness: CWE-502

2 references (advisories, patches, write-ups)

Sources: NVD, CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.

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