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Description

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

PUBLISHED Reserved 2026-02-11 | Published 2026-04-14 | Updated 2026-06-01 | Assigner microsoft




HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Problem types

CWE-20: Improper Input Validation

Product status

6.2.9200.0 (custom) before 6.2.9200.26026
affected

6.2.9200.0 (custom) before 6.2.9200.26026
affected

6.3.9600.0 (custom) before 6.3.9600.23132
affected

6.3.9600.0 (custom) before 6.3.9600.23132
affected

10.0.14393.0 (custom) before 10.0.14393.9060
affected

10.0.14393.0 (custom) before 10.0.14393.9060
affected

10.0.17763.0 (custom) before 10.0.17763.8644
affected

10.0.17763.0 (custom) before 10.0.17763.8644
affected

10.0.20348.0 (custom) before 10.0.20348.5020
affected

10.0.25398.0 (custom) before 10.0.25398.2274
affected

10.0.26100.0 (custom) before 10.0.26100.32690
affected

10.0.26100.0 (custom) before 10.0.26100.32690
affected

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26154 (Windows Server Update Service (WSUS) Tampering Vulnerability) vendor-advisory patch

cve.org (CVE-2026-26154)

nvd.nist.gov (CVE-2026-26154)

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