Improper input validation in Microsoft Windows Server 2012
CVE-2026-26154
Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
EPSS: 0.003 (52.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C.
Affected products
- Microsoft Windows Server 2012 — versions 6.2.9200.0
- Microsoft Windows Server 2012 R2 — versions 6.3.9600.0
- Microsoft Windows Server 2012 R2 (Server Core Installation) — versions 6.3.9600.0
- Microsoft Windows Server 2012 (Server Core Installation) — versions 6.2.9200.0
- Microsoft Windows Server 2016 — versions 10.0.14393.0
- Microsoft Windows Server 2016 (Server Core Installation) — versions 10.0.14393.0
- Microsoft Windows Server 2019 — versions 10.0.17763.0
- Microsoft Windows Server 2019 (Server Core Installation) — versions 10.0.17763.0
- Microsoft Windows Server 2022 — versions 10.0.20348.0
- Microsoft Windows Server 2022, 23h2 Edition (Server Core Installation) — versions 10.0.25398.0
Weakness classification (CWE)
References
- Windows Server Update Service (WSUS) Tampering Vulnerability (vendor-advisory, patch)
Frequently asked questions
- What is CVE-2026-26154?
- CVE-2026-26154 is a high-severity vulnerability in Microsoft Windows Server 2012, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-04-14.
- How severe is CVE-2026-26154?
- High severity. CVSS v3 base score is 7.5 out of 10.