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Microsoft Security Response CenterCVE-2026-54998

Microsoft Exchange Online Elevation of Privilege Vulnerability

Incorrect authorization in Microsoft Exchange Online allows an authorized attacker to elevate privileges over a network.

Read the vendor bulletin Get alerts for Microsoft Exchange Online
8.8CVSS out of 10Critical severity
Scope

What the vendor says is affected

  • Microsoft Exchange Online
Timeline

When this advisory changed

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2026-54998View CVSS, KEV, EPSS, and threat context
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