CVE intelligence

CVE-2026-54998

Vulnerability intelligence

Published Jul 2, 2026Sources checked Sep 28, 2026

8.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-54998 and is rated High severity with a CVSS score of 8.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.8%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-54998?

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