CVE-2026-39822
Root escape via symlink plus trailing slash in os
Description
On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root.
INFO
Published Date :
July 8, 2026, 5:17 p.m.
Last Modified :
July 13, 2026, 2:54 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Ensure symlinks are not followed when they point outside the root.
- Validate path components before opening files.
- Update the file handling logic to reject such symlinks.
Public PoC/Exploit Available at Github
CVE-2026-39822 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-39822.
| URL | Resource |
|---|---|
| https://go.dev/cl/797880 | Patch |
| https://go.dev/issue/79005 | Issue Tracking Patch |
| https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc | Mailing List Patch Vendor Advisory |
| https://pkg.go.dev/vuln/GO-2026-4970 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-39822 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-39822
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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None
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-39822 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-39822 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 13, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* versions up to (excluding) 1.25.12 *cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* versions from (including) 1.26.0 up to (excluding) 1.26.5 *cpe:2.3:a:golang:go:1.27:rc1:*:*:*:*:*:* Added Reference Type Go Project: https://go.dev/cl/797880 Types: Patch Added Reference Type Go Project: https://go.dev/issue/79005 Types: Issue Tracking, Patch Added Reference Type Go Project: https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc Types: Mailing List, Patch, Vendor Advisory Added Reference Type Go Project: https://pkg.go.dev/vuln/GO-2026-4970 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-61 Added SSVC {'id': 'CVE-2026-39822', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-08T18:06:16.360721Z'} -
New CVE Received by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Go standard library', 'product': 'os', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '1.25.12', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.26.0-0', 'lessThan': '1.26.5', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.27.0-0', 'lessThan': '1.27.0-rc.2', 'versionType': 'semver'}], 'packageName': 'os', 'collectionURL': 'https://pkg.go.dev', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'rootOpenFileNolog'}, {'name': 'openRootInRoot'}, {'name': 'OpenInRoot'}, {'name': 'Root.Create'}, {'name': 'Root.Open'}, {'name': 'Root.OpenFile'}, {'name': 'Root.OpenRoot'}, {'name': 'Root.ReadFile'}, {'name': 'Root.WriteFile'}, {'name': 'rootFS.Open'}, {'name': 'rootFS.ReadDir'}, {'name': 'rootFS.ReadFile'}]}] Added Description On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root. Added Reference https://go.dev/cl/797880 Added Reference https://go.dev/issue/79005 Added Reference https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc Added Reference https://pkg.go.dev/vuln/GO-2026-4970