CVE-2026-58644: Microsoft SharePoint

What is CVE-2026-58644?

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

CVSS9.8 NVD 3.1

SeverityCRITICAL

Exploitation In the wild In CISA KEV

EPSS16% · P97

Triage statusActive Exploit

ActionPatch immediately

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWECWE-502

NVD published2026-07-14

NVD last modified2026-07-17

Timeline

2026-07-14Published to the U.S. National Vulnerability Database (NVD)
2026-07-16Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
2026-07-17NVD record last updated
2026-07-19CISA federal remediation deadline (BOD 22-01)

CISA Known Exploited Vulnerability

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Added to KEV2026-07-16

Federal patch deadline2026-07-19

Known ransomware useUnknown

Affected product

Microsoft SharePoint

Remediation Steps

Apply the vendor security update for Microsoft SharePoint as a priority.
Restrict network exposure of the affected service to trusted sources until patched.
Review logs and detections for indicators of exploitation.
Confirm fixed versions against the official vendor advisory before deploying.

References

Referenced in our briefings & reports

Vulnerability Priority Report – Week 2 of August 2026 (August 10 – 16)
Vulnerability Priority Report – Week 1 of August 2026 (August 3 – 9)
Vulnerability Priority Report – Week 4 of July 2026 (July 27 – August 2)
Vulnerability Priority Report – Week 3 of July 2026 (July 20 – 26)
Vulnerability Priority Report – Week 2 of July 2026 (July 13 – 19)

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🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.