Summary
Impact: Remote Code Execution. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
How could an attacker exploit this vulnerability?
An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is 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 win a race condition.
Security updates
10.0.17763.9121 — https://support.microsoft.com/help/5120238
10.0.20348.5499 — https://support.microsoft.com/help/5120242
10.0.20348.5440 — https://support.microsoft.com/help/5120229
10.0.19044.7663 — https://support.microsoft.com/help/5120249
10.0.26100.33296 — https://support.microsoft.com/help/5120233
10.0.26100.33222 — https://support.microsoft.com/help/5120228
10.0.26200.9168 — https://support.microsoft.com/help/5121003
10.0.26200.9106 — https://support.microsoft.com/help/5120994
10.0.22631.7517 — https://support.microsoft.com/help/5120240
10.0.28000.2704 — https://support.microsoft.com/help/5121000
10.0.14393.9418 — https://support.microsoft.com/help/5120418
6.2.9200.26280 — https://support.microsoft.com/help/5120386
6.3.9600.23338 — https://support.microsoft.com/help/5120385
Vulnerabilities 1
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High 8.1
Windows Secure Socket Tunneling Protocol (SSTP) Remote Code Execution Vulnerability
Double free in Windows Secure Socket Tunneling Protocol (SSTP) allows an unauthorized attacker to execute code over a network.
Revision history
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#2
Updated an acknowledgement. This is an informational change only.
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#1
Information published.
References
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CVE-2026-62889 Windows Secure Socket Tunneling Protocol (SSTP) Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62889
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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