CVE-2022-41720

Restricted file access on Windows in os and net/http

Published Dec 7, 2022 CVSS 3.1 · 7.5 High EPSS 1.3% KEV · Not listed
Description
On Windows, restricted files can be accessed via os.DirFS and http.Dir. The os.DirFS function and http.Dir type provide access to a tree of files rooted at a given directory. These functions permit access to Windows device files under that root. For example, os.DirFS("C:/tmp").Open("COM1") opens the COM1 device. Both os.DirFS and http.Dir only provide read-only filesystem access. In addition, on Windows, an os.DirFS for the directory (the root of the current drive) can permit a maliciously crafted path to escape from the drive and access any path on the system. With fix applied, the behavior of os.DirFS("") has changed. Previously, an empty root was treated equivalently to "/", so os.DirFS("").Open("tmp") would open the path "/tmp". This now returns an error.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2022-44894 On Windows, restricted files can be accessed via os.DirFS and http.Dir. The os.DirFS function and http.Dir type provide access to a tree of files rooted at a given directory. These functions permit access to Windows device files under that root. For example, os.DirFS("C:/tmp").Open("COM1") opens the COM1 device. Both os.DirFS and http.Dir only provide read-only filesystem access. In addition, on Windows, an os.DirFS for the directory (the root of the current drive) can permit a maliciously crafted path to escape from the drive and access any path on the system. With fix applied, the behavior of os.DirFS("") has changed. Previously, an empty root was treated equivalently to "/", so os.DirFS("").Open("tmp") would open the path "/tmp". This now returns an error.
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Go
Published
Updated
Apr 23, 2025, 3:43 PM
Reserved
Sep 28, 2022, 5:00 PM
Status
Modified
Published
Dec 7, 2022, 5:15 PM
Modified
Jun 17, 2026, 5:03 AM
Severity
Important
Public date
Dec 7, 2022, 12:00 AM