by Kastro CVE-2026-56857
Go standard library os — Root.Mkdir(All) can follow junctions out of the root on Windows in os
Description · from the CVE record
On Windows, when the target of Root.Mkdir or Root.MkdirAll is a junction pointing to an empty location, the operation can create a directory at the junction target even when that target is located outside the root. This only applies to operations where the last path component is a junction (path/to/junction, but not path/junction/target).
Affected
ProductAffectedFixed inSource
os< 1.26.91.26.9CNA
os1.27.0-0 – < 1.27.21.27.2CNA
internal/syscall/windows< 1.26.91.26.9CNA
internal/syscall/windows1.27.0-0 – < 1.27.21.27.2CNA
Scores by source
CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total