It was possible to improperly access the parent directory of an os.Root by opening a filename ending in "../". For example, Root.Open("../") would open the parent directory of the Root. This escape only permits opening the parent directory itself, not ancestors of the parent or files contained within the parent.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 5
https://go.dev/cl/670036
security@golang.org
https://go.dev/issue/73555
security@golang.org
https://groups.google.com/g/golang-announce/c/UZoIkUT367A/m/5WDxKizJAQAJ
security@golang.org
https://pkg.go.dev/vuln/GO-2026-4403
security@golang.org
http://www.openwall.com/lists/oss-security/2025/05/06/2
af854a3a-2127-422b-91ae-364da2661108