CVE-2026-20856

HIGH EPSS 60.8%
Published Jan 13, 20265mo ago · Modified Jun 17, 20261w ago
8.1 CVSS 3.1
High
Find Similar
Published Jan 13, 2026 5mo ago
Last Modified Jun 17, 2026 1w ago

Description

Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.

CVSS Details

Base Score
8.1
Exploitability
2.2
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
60.8% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-20 Improper Input Validation Validation

Affected Products 16

VendorProductVersionRange
microsoftwindows_10_1607* <10.0.14393.8783
microsoftwindows_10_1607* <10.0.14393.8783
microsoftwindows_10_1809* <10.0.17763.8276
microsoftwindows_10_1809* <10.0.17763.8276
microsoftwindows_10_21h2* <10.0.19044.6809
microsoftwindows_10_22h2* <10.0.19045.6809
microsoftwindows_11_23h2* <10.0.22631.6491
microsoftwindows_11_24h2* <10.0.26100.7623
microsoftwindows_11_25h2* <10.0.26200.7623
microsoftwindows_server_2012*any
microsoftwindows_server_2012r2any
microsoftwindows_server_2016* <10.0.14393.8783
microsoftwindows_server_2019* <10.0.17763.8276
microsoftwindows_server_2022* <10.0.20348.4648
microsoftwindows_server_2022_23h2* <10.0.25398.2092
microsoftwindows_server_2025* <10.0.26100.32230

References 1

  • msrc.microsoft.com https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20856
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.