8.0High
Microsoft Windows 10 1607
CVE-2026-40400
Relative path traversal in Windows PowerShell allows an authorized attacker to execute code over a network.
What this means for your business
- It affects Microsoft Windows 10 1607. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, with an ordinary user login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.9% chance of attack attempts being seen in the next 30 days, ranking above 57% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Microsoft Windows 10 1607, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 8.0 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H- Weakness
- CWE-23
- Assigned by
- secure@microsoft.com
Dates
- Published
- 2026-07-14
- Last modified
- 2026-09-17
- Sources
- NVD
Affected products
- Microsoft Windows 10 1607- 10.0.14393.9339
- Microsoft Windows 10 1809- 10.0.17763.9020
- Microsoft Windows 10 21h2- 10.0.19044.7548
- Microsoft Windows 10 22h2- 10.0.19045.7548
- Microsoft Windows 11 24h2- 10.0.26100.8875
- Microsoft Windows 11 25h2- 10.0.26200.8875
- Microsoft Windows 11 26h1- 10.0.28000.2269
- Microsoft Windows Server 2012all versions, r2
- Microsoft Windows Server 2016- 10.0.14393.9339
- Microsoft Windows Server 2019- 10.0.17763.9020
- Microsoft Windows Server 2022- 10.0.20348.5386
- Microsoft Windows Server 2025- 10.0.26100.33158
As listed in the NVD configuration data. Not a statement about your estate.