Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Windows_server_2012 | Microsoft | - (including) | - (including) |
| Windows_server_2012 | Microsoft | r2 (including) | r2 (including) |
| Windows_server_2016 | Microsoft | * | 10.0.14393.8524 (excluding) |
| Windows_server_2019 | Microsoft | * | 10.0.17763.7922 (excluding) |
| Windows_server_2022 | Microsoft | * | 10.0.20348.4297 (excluding) |
| Windows_server_2022_23h2 | Microsoft | * | 10.0.25398.1916 (excluding) |
| Windows_server_2025 | Microsoft | * | 10.0.26100.6905 (excluding) |
Potential Mitigations
- Make fields transient to protect them from deserialization.
- An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
Related Attack Patterns
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59287
- https://hawktrace.com/blog/CVE-2025-59287
- https://www.bleepingcomputer.com/news/security/cisa-orders-feds-to-patch-windows-server-wsus-flaw-exploited-in-attacks/
- https://www.vicarius.io/vsociety/posts/cve-2025-59287-detection-script-rce-vulnerability-in-windows-server-update-service
- https://www.vicarius.io/vsociety/posts/cve-2025-59287-mitigation-script-rce-vulnerability-in-windows-server-update-service
- https://gist.github.com/hawktrace/880b54fb9c07ddb028baaae401bd3951
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59287