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
-
High 8.1
Microsoft Exchange Server Remote Code Execution Vulnerability
Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.
Revision history
-
#1
Information published.
References
-
CVE-2026-55007 Microsoft Exchange Server Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55007
-
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
-
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
-
Common Vulnerability Scoring System
https://www.first.org/cvss