---
title: "CVE-2025-59287: Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability"
url: https://erroneo.us/security/cve/CVE-2025-59287/
description: "CVE-2025-59287 (Microsoft Windows): Exploited in the wild (CISA KEV). Deserialization of untrusted data in Windows Server Update Service allows an…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-10-14
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-59287"
kev: true
cvss: 9.8
epss: 0.9998
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-59287: Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Microsoft Windows. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-10-24, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-11-14 ; treat that as the outer limit, not the target.
- EPSS 100.0% , percentile 100.0: FIRST’s model estimates a 100.0% chance of exploitation activity in the next 30 days, higher than 100.0% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Patch this week. Microsoft WSUS CVE-2025-59287: Unauthenticated SYSTEM RCE — Only servers with the WSUS role are at risk, but on those it is unauthenticated SYSTEM code execution: patch them now, and treat any WSUS server exposed on 8530/8531 to the internet as a likely incident.

## What it is

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

## Affected products (CVE record)

- Microsoft Windows Server 2012: 6.2.9200.0 < 6.2.9200.25728
- Microsoft Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.25728
- Microsoft Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.22826
- Microsoft Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.22826
- Microsoft Windows Server 2016: 10.0.14393.0 < 10.0.14393.8524
- Microsoft Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.8524
- Microsoft Windows Server 2019: 10.0.17763.0 < 10.0.17763.7922
- Microsoft Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.7922
- Microsoft Windows Server 2022: 10.0.20348.0 < 10.0.20348.4297
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): 10.0.25398.0 < 10.0.25398.1916

## Severity

- microsoft CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C`

## Exploitation

- CISA KEV: added 2025-10-24; federal due date 2025-11-14. Known ransomware use: Unknown.
- CISA required action: 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 SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 99.98% probability of exploitation activity in the next 30 days; percentile 100.0.

## Sources

- [Windows Server Update Service (WSUS) Remote Code Execution Vulnerability](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59287)
- [Listed in CISA KEV notes (msrc.microsoft.com)](https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-59287)
- [CVE.org record CVE-2025-59287](https://www.cve.org/CVERecord?id=CVE-2025-59287)
- [NVD entry CVE-2025-59287](https://nvd.nist.gov/vuln/detail/CVE-2025-59287)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59287)
- [gist.github.com](https://gist.github.com/hawktrace/880b54fb9c07ddb028baaae401bd3951)
- [bleepingcomputer.com](https://www.bleepingcomputer.com/news/security/cisa-orders-feds-to-patch-windows-server-wsus-flaw-exploited-in-attacks/)
- [hawktrace.com](https://hawktrace.com/blog/CVE-2025-59287)
- [vicarius.io](https://www.vicarius.io/vsociety/posts/cve-2025-59287-detection-script-rce-vulnerability-in-windows-server-update-service)
- [vicarius.io](https://www.vicarius.io/vsociety/posts/cve-2025-59287-mitigation-script-rce-vulnerability-in-windows-server-update-service)

---
Source page: https://erroneo.us/security/cve/CVE-2025-59287/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt