CVE-2026-56857 Windows - Path Traversal

Windows file system operations Root.Mkdir and Root.MkdirAll contain a path traversal vulnerability caused by improper handling of junction points, letting attackers create directories outside the root, exploit requires a junction pointing to an empty location.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.49% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Path Traversal
Impact
File System Write
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
8 October 2026
Updated
15 October 2026
Weakness
CWE-1386

Vendor fix

Update to the latest Windows version with patched file system handling.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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