CVE WatchJul 17, 2026

CVE-2026-58644

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

CVSS

9.8

Critical

EPSS

15.9%

p97

KEV

YES

Jul 16, 2026

Exploit Today

0-100

Published: Jul 14, 2026 · Last modified: Jul 17, 2026 · CWE-502

EPSS · 30d

6.0%EPSS · 30 days45.5%

2026-08-022026-08-30

KEV catalog record

Product

Microsoft / SharePoint

Vulnerability

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Added to KEV

Jul 16, 2026

Remediate by

Jul 19, 2026

Known ransomware use

Summary description

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

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.

Notes

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-58644

Technical description

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

Official references

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