CVE-2026-55040
Last modified
CVE-2026-55040 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.. CISA has confirmed active exploitation in the wild. EPSS estimates a 3.97% chance of exploitation in the next 30 days.
Description
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
Metrics
Exploitation Status
This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by .
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Sharepoint Server | < 16.0.19725.20434 |
| Microsoft | Sharepoint Server | 2016 |
| Microsoft | Sharepoint Server | 2019 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55040Exploit, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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