CVE-2026-63523Network attack vector

Spoofing via improper web-input neutralization

Published Sep 8, 2026 · Updated Sep 10, 2026

Cross-site scripting in Microsoft Skype for Business Server allows remote attackers to spoof content through network-delivered input. Microsoft has not disclosed the affected page or component, the input field involved, or how untrusted input reaches generated web content without neutralization. Exploitation requires no prior privileges but requires victim interaction; the reported consequence is spoofed content and exposure of confidential data.

CVSS severity6.5
Medium
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Microsoft Skype for Business Server allows remote attackers to spoof content through network-delivered input. Microsoft has not disclosed the affected page or component, the input field involved, or how untrusted input reaches generated web content without neutralization. Exploitation requires no prior privileges but requires victim interaction; the reported consequence is spoofed content and exposure of confidential data.

The record

CVE
CVE-2026-63523
Published
Sep 8, 2026
Updated
Sep 10, 2026
Vendor
Microsoft
Product
Skype for Business Server Subscription Edition
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2046.0 <7.0.2046.879

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Skype for Business Server Subscription Editionversion=2046.0 <7.0.2046.879
Microsoft · Skype for Business Serverversion=2046.0 <7.0.2046.569; version=9319.0 <6.0.9319.885

Published CVSS scores

6.5MicrosoftCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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