CVE-2026-66305
HIGHCVSS 7.1/10EPSS 0.30%
Last modified
CVE-2026-66305 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.. EPSS estimates a 0.30% chance of exploitation in the next 30 days.
Description
Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Microsoft | Skype For Business Server | 2015 | Cumulative Update 13 |
| Microsoft | Skype For Business Server | 2019 | Cumulative Update 8 |
| Microsoft | Skype For Business Server Subscription Edition | 7.0.2046.849 | — |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66305Patch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-66305?
Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.
How severe is CVE-2026-66305?
CVE-2026-66305 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.
How do I fix CVE-2026-66305?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
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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Are you affected by CVE-2026-66305?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST