CVE-2026-55040
Microsoft SharePoint Server Security Feature Bypass Vulnerability
CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
| Vendor | microsoft |
| Product | microsoft sharepoint enterprise server 2016 |
| Ecosystems | |
| Industries | TechnologyEnterprise |
| Published | Jul 14, 2026 |
| Last Updated | Aug 28, 2026 |
⚠️ Actively Exploited — Act Now
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CVSS v3 Breakdown
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
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
Microsoft / Microsoft SharePoint Enterprise Server 2016
16.0.0 < 16.0.5561.1001
Microsoft / Microsoft SharePoint Server 2019
16.0.0 < 16.0.10417.20175
Microsoft / Microsoft SharePoint Server Subscription Edition
16.0.0 < 16.0.19725.20434
References
msrc.microsoft.com: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040 rapid7.com: https://www.rapid7.com/blog/post/ra-microsoft-sharepoint-jwt-token-authentication-bypass-cve-2026-55040/ github.com: https://github.com/sfewer-r7/CVE-2026-55040 cisa.gov: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55040