CVE-2021-26421
MEDIUMCVSS 6.5/10EPSS 1.41%
Last modified
CVE-2021-26421 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. Skype for Business and Lync Spoofing Vulnerability. EPSS estimates a 1.41% chance of exploitation in the next 30 days.
Description
Skype for Business and Lync Spoofing Vulnerability
Metrics
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Microsoft | Lync Server | 2013 | Cumulative Update 10 |
| Microsoft | Skype For Business Server | 2015 | Cumulative Update 11 |
References
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26421Patch, Vendor Advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26421Patch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-26421?
Skype for Business and Lync Spoofing Vulnerability
How severe is CVE-2021-26421?
CVE-2021-26421 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.41% probability of exploitation in the next 30 days.
How do I fix CVE-2021-26421?
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-2021-26421?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST