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PatchSiren cyber security CVE debrief

CVE-2026-63523 Microsoft CVE debrief

A cross-site scripting vulnerability in Skype for Business allows an unauthorized attacker to perform spoofing over a network. The CVE record was published on 2026-09-08T19:18:07.267Z and has not been modified since then. The NVD entry is currently Undergoing Analysis. This vulnerability affects Skype for Business deployments, which may be exposed to potential spoofing attacks. Defenders should verify exposure and assess the impact of these attacks on business operations. The CVE Program and NVD provide official information on this vulnerability.

Vendor
Microsoft
Product
Skype for Business Server 2015 CU13
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-11
Advisory published
2026-09-08
Advisory updated
2026-09-11

Who should care

Defenders responsible for Skype for Business deployments should assess exposure and prioritize verification of potential spoofing attacks. They should also review official advisories and CVE records to validate affected scope, severity, and vendor guidance. Additionally, defenders should plan vendor-supported updates or mitigations through normal change control where exposure is confirmed and review compensating for

Why it matters

Defenders should prioritize verifying exposure in Skype for Business deployments and assessing the impact of potential spoofing attacks due to the cross-site scripting vulnerability.

  • Verify exposure in Skype for Business deployments to prevent potential spoofing attacks
  • Assess the impact of potential spoofing attacks on business operations
  • Monitor for updates from Microsoft on this vulnerability to ensure timely remediation

Technical summary

The vulnerability is due to improper neutralization of input during web page generation, allowing an unauthorized attacker to perform spoofing over a network. This cross-site scripting vulnerability affects Skype for Business deployments, which may be exposed to potential spoofing attacks if not properly mitigated. The official CVE record and NVD detail page provide information on the vulnerability, but the scope of affected versions and remediation steps require verification from official sources.

Defensive priority

Defenders should prioritize verifying exposure in Skype for Business deployments and assessing the impact of potential spoofing attacks.

Recommended defensive actions

  • Verify exposure in Skype for Business deployments
  • Assess the impact of potential spoofing attacks
  • Monitor for updates from Microsoft on this vulnerability

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, but the scope of affected versions and remediation steps require verification from official sources.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-63523 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-63523

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-63523 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-63523

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.