Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 99.9%; technical severity is CVSS 9.8.
Deserialization of untrusted data in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
Who should care
- Teams operating Windows, Windows Server 2012, Windows Server 2016 +4 more
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Windows, Windows Server 2012, Windows Server 2016 +4 more is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Vendor remediation
Patch and remediation links
Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-502
- Affected versions
- Microsoft Windows; Microsoft Windows Server 2012 (Version: r2); Microsoft Windows Server 2016 (End Excluding: 10.0.14393.8524); Microsoft Windows Server 2019 (End Excluding: 10.0.17763.7922); Microsoft Windows Server 2022 (End Excluding: 10.0.20348.4297); Microsoft Windows Server 2022 23h2 (End Excluding: 10.0.25398.1916); Microsoft Windows Server 2025 (End Excluding: 10.0.26100.6905)
- Published
- 14 October 2025
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Added to CISA KEV
- Latest EPSS score: 99.9%
- Signal calculated at 85