CVE-2026-26154
Windows Server Update Service (WSUS) Tampering Vulnerability
Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Windows Server Update Service (WSUS) Tampering Vulnerability
Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.
- Record
CVE-2026-26154- CVSS 3.1
- 7.5 High
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 - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2026-22376
Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.
- Record
EUVD-2026-22376- CVSS 3.1
- 7.5 High
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xm9h-x34f-j9hj
Improper input validation in Windows Server Update Service allows an unauthorized attacker to...
Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.
- Record
GHSA-xm9h-x34f-j9hj- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.
- Record
CVE-2026-26154- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
- microsoft windows server 2012
- microsoft windows server 2012 (server core installation)
- microsoft windows server 2012 r2
- microsoft windows server 2012 r2 (server core installation)
- microsoft windows server 2016
- microsoft windows server 2016 (server core installation)
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
- microsoft windows server 2022
- microsoft windows server 2022, 23h2 edition (server core installation)
- microsoft windows server 2025
- microsoft windows server 2025 (server core installation)
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History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-26154 is a high vulnerability (CVSS 7.5) in Microsoft Windows Server 2012, published April 14, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.06%, the 64th percentile. No source names a fixed version.