Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability

CRITICAL 9.8EXPLOITED (CISA KEV)CVE-2025-59287 · Published 14/10/2025 · updated 17/06/2026

Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 24/10/2025. Patch affected systems as an emergency.

Package	Affected versions	Patched versions
Windows Microsoft	Versions not published yet (product named by CISA KEV)

Description

Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59287 · Vendor Advisory
hawktrace.com/blog/CVE-2025-59287 · Exploit
bleepingcomputer.com/news/security/cisa-orders-feds-to-patch-windows-server-wsus-flaw-exploited-in-attacks · Press/Media Coverage
vicarius.io/vsociety/posts/cve-2025-59287-detection-script-rce-vulnerability-in-windows-server-update-service · Third Party Advisory
vicarius.io/vsociety/posts/cve-2025-59287-mitigation-script-rce-vulnerability-in-windows-server-update-service · Mitigation
gist.github.com/hawktrace/880b54fb9c07ddb028baaae401bd3951 · Third Party Advisory
cisa.gov/known-exploited-vulnerabilities-catalog · Third Party Advisory
CISA KEV · CVE-2025-59287

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