XSS in Microsoft Skype For Business Server
CVE-2026-63523
Improper neutralization of input during web page generation ('cross-site scripting') in Skype for Business allows an unauthorized attacker to perform spoofing over a network.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.006 (45.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Microsoft Skype For Business Server — versions 2015, 2019
- Microsoft Skype For Business Server 2015 Cu13
- Microsoft Skype For Business Server Subscription Edition — versions 7.0.2046.849
Weakness classification (CWE)
References
- Skype for Business Spoofing Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-63523?
- CVE-2026-63523 is a medium-severity vulnerability in Microsoft Skype For Business Server, classified under Cross-site Scripting. CVSS score: 6.5/10. Published 2026-09-08.
- How severe is CVE-2026-63523?
- Medium severity. CVSS v3 base score is 6.5 out of 10.