CVE-2025-59287
Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability
Microsoft Windows
Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 24 October 2025. US federal agencies were required to remediate it by 14 November 2025.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 100%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2025-59287 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2025-59287.
What does CVE-2025-59287 affect?
CVE-2025-59287 affects Microsoft Windows. Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
How severe is CVE-2025-59287?
CVE-2025-59287 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 100%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 14 November 2025.
How should organisations respond to CVE-2025-59287?
Apply the vendor patch for Microsoft Windows as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.