Windows Deployment Services TFTP Server Remote Code Execution Vulnerability

Assessment

Use after free in Windows Deployment Services allows an unauthorized attacker to execute code over a network.

Severity
Critical
CVSS base score
9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Impact
Remote Code Execution
EPSS, next 30 days
1.0%Higher than 60.5% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
Exploitability
Exploitation More Likely
Publicly disclosed
No
Customer action
Required: apply the update
Component
Windows Deployment Services
Weakness
CWE-416: Use After Free
Issued by
Microsoft
Published
11 Aug 2026 · August 2026
Last revised
8 Sep 2026Updated software table to remove clients versions because this vulnerability only impacts Windows Servers. This is an informational change only.

Updates that fix it

8 KBs
KBTypeRestartApplies toOther CVEs
KB5120228 Security Hotpatch Update Required Windows Server 2025, Windows Server 2025 (Server Core installation) All CVEs in KB5120228
KB5120229 Security Hotpatch Update Required Windows Server 2022, Windows Server 2022 (Server Core installation) All CVEs in KB5120229
KB5120233 Security Update Required Windows Server 2025, Windows Server 2025 (Server Core installation) All CVEs in KB5120233
KB5120238 Security Update Required Windows Server 2019, Windows Server 2019 (Server Core installation) All CVEs in KB5120238
KB5120242 Security Update Required Windows Server 2022, Windows Server 2022 (Server Core installation) All CVEs in KB5120242
KB5120385 Monthly Rollup Required Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) All CVEs in KB5120385
KB5120386 Monthly Rollup Required Windows Server 2012, Windows Server 2012 (Server Core installation) All CVEs in KB5120386
KB5120418 Security Update Required Windows Server 2016, Windows Server 2016 (Server Core installation) All CVEs in KB5120418

Affected products

ESU, Windows
12 affected products
  • Windows Server 2012
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)
  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows Server 2025
  • Windows Server 2025 (Server Core installation)
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