CVE-2025-59287Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via AuthorizationCookie deserialization

Published Oct 14, 2025 · Updated Oct 14, 2025

Unsafe deserialization in Microsoft WSUS on affected Windows Server releases allows remote attackers to execute code with SYSTEM privileges. EncryptionHelper.DecryptData decrypts an attacker-controlled AuthorizationCookie and passes its contents to BinaryFormatter without a safe type restriction. Exploitation requires the WSUS Server Role and network access to TCP ports 8530 or 8531; successful execution runs under SYSTEM.

CVSS severity9.8
Critical
EPSS probability99.98%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in Microsoft WSUS on affected Windows Server releases allows remote attackers to execute code with SYSTEM privileges. EncryptionHelper.DecryptData decrypts an attacker-controlled AuthorizationCookie and passes its contents to BinaryFormatter without a safe type restriction. Exploitation requires the WSUS Server Role and network access to TCP ports 8530 or 8531; successful execution runs under SYSTEM.

The record

CVE
CVE-2025-59287
Published
Oct 14, 2025
Updated
Oct 14, 2025
Vendor
Microsoft
Product
Windows Server 2019
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.17763.0 <10.0.17763.7919

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.7919
Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.6899
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.8519
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.25722
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.25722
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.1913
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.8519
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.22824
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.7919
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.4294
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.6899
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.22824

Published CVSS scores

9.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsShadowserver observations through Sep 15, 2026. Gaps indicate unavailable data.
Sep 9, 2026Sep 15, 2026
View daily counts
Reporting dayUnique IPs
Sep 9, 2026Unavailable
Sep 10, 2026Unavailable
Sep 11, 2026Unavailable
Sep 12, 2026Unavailable
Sep 13, 2026Unavailable
Sep 14, 20261
Sep 15, 2026Unavailable
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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