Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-63523

CVE-2026-63523MEDIUM

Microsoft Skype for Business Server 2015 CU13 — Skype for Business Spoofing Vulnerability

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   R  C  L  L  N    6.1   .0055   44.3     —

AFFECTED
  Product                                             Versions  Fixed
  Skype for Business Server 2015 CU13                 9319.0 –  —
  Skype for Business Server 2019 CU8                  2046.0 –  —
  Skype for Business Server Subscription Edition CU1  2046.0 –  —

TIMELINE
  Jul 16  Reserved by microsoft
  Sep 8   Published (CNA: microsoft)
  Sep 16  RESCORED — CVE-2026-63523 (Microsoft Skype for Business Server 2015 CU13). CVSS 6.5 → 6.1 (NVD).

CWE-79 · CNA: microsoft · CVSS v3.1 · 1 reference · NVD status: Analyzed

Description

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
July 16, 2026	Reserved	Reserved by microsoft
September 8, 2026	Published	Published (CNA: microsoft)
September 16, 2026	RESCORED	RESCORED — CVE-2026-63523 (Microsoft Skype for Business Server 2015 CU13). CVSS 6.5 → 6.1 (NVD).

Affected

Affected products and packages — 3 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Microsoft	Skype for Business Server 2015 CU13	—	9319.0	—
Microsoft	Skype for Business Server 2019 CU8	—	2046.0	—
Microsoft	Skype for Business Server Subscription Edition CU1	—	2046.0	—

Weaknesses

CWE-79

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63523 [vendor-advisory, patch]

Authoritative record: CVE-2026-63523 at cve.org

Vendors: microsoft

Weaknesses: CWE-79

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-63523 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.