Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-55946

CVE-2026-55946MEDIUM

Microsoft Copilot Information Disclosure Vulnerability

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   H   N   N  U  H  N  N    5.9   .0039   30.7     —

AFFECTED
  Product            Versions  Fixed
  Microsoft Copilot  - –       —

TIMELINE
  Jun 17  Reserved by microsoft
  Sep 17  Published (CNA: microsoft)
  Sep 25  RESCORED — CVE-2026-55946 (Microsoft Copilot). CVSS 6.1 → 5.9 (NVD).

CWE-77 · CNA: microsoft · CVSS v3.1 · 1 reference · NVD status: Analyzed

Description

Improper neutralization of special elements used in a command ('command injection') in Microsoft Copilot allows an unauthorized attacker to disclose information over a network.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
June 17, 2026	Reserved	Reserved by microsoft
September 17, 2026	Published	Published (CNA: microsoft)
September 25, 2026	RESCORED	RESCORED — CVE-2026-55946 (Microsoft Copilot). CVSS 6.1 → 5.9 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Microsoft	Microsoft Copilot	—	-	—

Weaknesses

CWE-77

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55946 [vendor-advisory, patch]

Authoritative record: CVE-2026-55946 at cve.org

Vendors: microsoft

Weaknesses: CWE-77

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-55946 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 Saturday, October 3, 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.