Summary
Impact: Remote Code Execution. Microsoft rating: Critical. Not known to be exploited — Exploitation More Likely. Customer action: Required.
Details
How could an attacker exploit this vulnerability?
An unauthenticated attacker could send a specially crafted email to an affected Exchange server, triggering an internal content-conversion process. Successful exploitation could allow the attacker to execute code on the server. Exploitation requires an attacker to have a deep understanding of the target environment and is not guaranteed to succeed. 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 of this vulnerability requires an attacker to have a deep understanding of the system. Successful exploitation is not guaranteed and depends on a combination of factors that might include the environment, system configuration, and the presence of additional security measures.
Security updates
15.02.1748.055 — https://support.microsoft.com/help/5128896
15.02.2562.056 — https://support.microsoft.com/help/5128895
15.01.2507.077 — https://support.microsoft.com/help/5128898
15.02.1544.050 — https://support.microsoft.com/help/5128897
Vulnerabilities 1
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High 8.1
Microsoft Exchange Server Remote Code Execution Vulnerability
Stack-based buffer overflow in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.
Revision history
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#1
Information published.
References
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CVE-2026-70571 Microsoft Exchange Server Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70571
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss