Windows Server Update Service Remote Code Execution Vulnerability
Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
MSRC compact vulnerability detail
CVE-2026-20856 · Windows Server Update Service (WSUS) Remote Code Execution Vulnerability
Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
Signals
Windows Server Update Service
Remote Code Execution
Exploited: No
Publicly disclosed: No
Exploitability: Exploitation Less Likely
CWE
Patch Diff
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Resolved binary override
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Description
Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
FAQ / Articles
FAQ
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? The attacker must inject themselves into the logical network path between the target and the resource requested by the victim to read or modify network communications. This is called a machine-in-the-middle (MITM) attack.