CVE-2025-59287
Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 14 November 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 99.98% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 24 October 2025 · due 14 November 2025
- Weakness
- CWE-502
- Affected
- microsoft/windows server 2012 · microsoft/windows server 2016 · microsoft/windows server 2019 · microsoft/windows server 2022 · microsoft/windows server 2022 23h2 · microsoft/windows server 2025
- Source
- secure@microsoft.com
EPSS 100.0% since 30 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-59287 ; https://nvd.nist.gov/vuln/detail/CVE-2025-59287
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59287Vendor Advisory
- https://hawktrace.com/blog/CVE-2025-59287Exploit, Third Party Advisory
- https://www.bleepingcomputer.com/news/security/cisa-orders-feds-to-patch-windows-server-wsus-flaw-exploited-in-attacks/Press/Media Coverage
- https://www.vicarius.io/vsociety/posts/cve-2025-59287-detection-script-rce-vulnerability-in-windows-server-update-serviceThird Party Advisory
- https://www.vicarius.io/vsociety/posts/cve-2025-59287-mitigation-script-rce-vulnerability-in-windows-server-update-serviceMitigation, Third Party Advisory
- https://gist.github.com/hawktrace/880b54fb9c07ddb028baaae401bd3951Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59287Third Party Advisory, US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.