CVE-2026-54998: Microsoft Exchange Online

High severity, CVSS 8.8. EPSS: 0.8% chance of exploitation in the next 30 days.

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

Affected products

• Microsoft Exchange Online: affected versions not specified

Published 2026-07-02. Last modified 2026-07-07.