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High MSRC-CVE-2026-55007 1 CVE

Microsoft Exchange Server Remote Code Execution Vulnerability

Published Sep 8, 2026 · Updated Sep 8, 2026

Summary

Impact: Remote Code Execution. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

How could an attacker exploit this vulnerability?
An unauthenticated attacker could send a specially crafted Visio attachment to an affected Exchange server. The server could process the attachment during content indexing, and successful exploitation could allow the attacker to execute code on the server. User interaction is not required.

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation requires the target system to be under sustained low-memory (memory pressure) conditions, which are not commonly present in normal operation. This makes the vulnerability difficult to reliably trigger, as the attacker must first induce or wait for a constrained memory state before exploitation becomes possible.

Security updates
15.02.1544.046 — https://support.microsoft.com/help/5121610
15.02.1748.051 — https://support.microsoft.com/help/5121609
15.02.2562.049 — https://support.microsoft.com/help/5121608

Vulnerabilities 1

Revision history

  1. #1

    Information published.

References