Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability
Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
What happened
Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
CISA lists it as exploited, added 24 Oct 2025.
Does it affect you
Names Microsoft Windows Server. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Follow the vendor advisory for the fixed release and any interim mitigation.
msrc.microsoft.com - Follow the vendor advisory for the fixed release and any interim mitigation.
vicarius.io - Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
cisa.gov
CISA’s notes for this entry:
Affected, as published to NVD
- ms-winserver
- Microsoft Windows Server: everything below 10.0.14393.8524
The record
- NVD status
- Analyzed
- Published
- 14 Oct 2025, last modified 17 Jun 2026 (NVD)
- Severity
- CVSS 3.1 base score 9.8, Critical — computed here from the vector; NVD states 9.8.
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness
- CWE-502 Deserialization of Untrusted Data (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 24 Oct 2025; federal remediation due 14 Nov 2025. CISA entry
- Exploit probability
- EPSS 100.0%, 100th percentile — FIRST, scored 23 Oct 2026. FIRST EPSS
- Vendor
- Microsoft · Windows (CISA)
References on the NVD record
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59287Vendor Advisory
- vicarius.io/vsociety/posts/cve-2025-59287-mitigation-script-rce-vulnerability-in-windows-server-update-serviceMitigationThird Party Advisory
- hawktrace.com/blog/CVE-2025-59287ExploitThird Party Advisory
- vicarius.io/vsociety/posts/cve-2025-59287-detection-script-rce-vulnerability-in-windows-server-update-serviceThird Party Advisory
- gist.github.com/hawktrace/880b54fb9c07ddb028baaae401bd3951Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59287Third Party AdvisoryUS Government Resource
- bleepingcomputer.com/news/security/cisa-orders-feds-to-patch-windows-server-wsus-flaw-exploited-in-attacks/Press/Media Coverage
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.