Microsoft Office SharePoint
CVE-2026-55040 — Microsoft SharePoint Server Security Feature Bypass Vulnerability
Executive Summary
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
Overview
9.1
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.9
EPSS Score
0.03971
probability of exploitation in the next 30 days
0.89555 percentile - updated 2026-08-14
View on FIRST.org
Affected Products
3 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft SharePoint Enterprise Server 2016 | 5002891 (Security Update) |
Critical | Security Feature Bypass | Maybe |
| Microsoft SharePoint Server 2019 | 5002883 (Security Update) |
Critical | Security Feature Bypass | Maybe |
| Microsoft SharePoint Server Subscription Edition | 5002882 (Security Update) |
Critical | Security Feature Bypass | Maybe |
Patches
3 patches
| Article | Type | Restart |
|---|---|---|
5002891 |
Security Update | Maybe |
5002883 |
Security Update | Maybe |
5002882 |
Security Update | Maybe |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
References
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