CVE-2026-55040: Microsoft Sharepoint Server

What is CVE-2026-55040?

Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.

CVSS9.1 NVD 3.1

SeverityCRITICAL

ExploitationNo exploitation reported

EPSS2% · P74

Triage statusNo Known Exploit

ActionPatch within 48 hours

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

CWECWE-1390

NVD published2026-07-14

NVD last modified2026-07-15

Timeline

2026-07-14Published to the U.S. National Vulnerability Database (NVD)
2026-07-15NVD record last updated
2026-08-12First covered in a defend.network daily briefing

Affected product

Microsoft Sharepoint Server

Remediation Steps

Apply Microsoft patches to all affected SharePoint Server versions
Implement network segmentation to restrict SharePoint server access
Enforce multi-factor authentication on all administrative SharePoint accounts
Audit SharePoint access logs for unauthorized administrative activity
Consider disabling unauthenticated access features if not required

References

Referenced in our briefings & reports

Vulnerability Priority Report – Week 2 of August 2026 (August 10 – 16)
Windows kernel zero-day exploited; Zoom annotation RCE, Sandworm VPN campaign (2026-08-12)

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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.