Root.Mkdir(All) can follow junctions out of the root on Windows in os (Go standard library os)

CVE-2026-56857
CRITICAL 9.8

At a glance

Source
NVD
EPSS
EPSS 0.55 % · percentile 46 ()
State
PUBLISHED
Published
Updated
Assigner
Go
NVD status
Awaiting Analysis

Description

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).

Weaknesses (CWE)

  • CWE-1386 — Insecure Operation on Windows Junction / Mount Point

References

Scores

VersionScoreVectorScored by
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCISA-ADP
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Advisories

European references

CERT-FR advisories

Affected products

ProductVersions
Go standard library · osaffected 0 < 1.26.9 ; affected 1.27.0-0 < 1.27.2
Go standard library · internal/syscall/windowsaffected 0 < 1.26.9 ; affected 1.27.0-0 < 1.27.2

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD