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Wagtail CMS suffers from an authorization bypass vulnerability in its snippet copy functionality, identified under GitHub Security Advisory GHSA-x5cx-w6p2-mxf2. The flaw resides in the permission validation logic when a user initiates a copy operation on a snippet model. In Wagtail, snippets are reusable content fragments that can be managed through the admin interface. Each snippet model is protected by a permission system that distinguishes between “add”, “change”, and “view” capabilities. Normally, a user must possess both “add” and “view” permissions to copy an existing snippet, as copying inherently requires reading the source object’s data.
However, the vulnerable code path within the snippet copy endpoint does not enforce a proper permission check on the source snippet instance. When a CMS user has only the “add” permission for a given snippet model but lacks explicit “change” or “view” permissions, the system incorrectly allows them to copy any existing snippet of that model type. The copy operation proceeds without verifying whether the user is authorized to view the source snippet’s content. As a result, the user can trigger a copy action that fetches the source snippet’s data, duplicates it, and presents the duplicated content—thereby exposing the original snippet’s sensitive fields to the unauthorized user.
The vulnerability is particularly dangerous because snippet models often store configuration data, contact information, or other sensitive business logic that should remain restricted. An attacker with minimal privileges (“add” only) can enumerate snippet IDs and copy each one to exfiltrate their contents. The attack is performed entirely within the Wagtail admin interface, requiring no special tools beyond authenticated access. The issue affects all Wagtail versions prior to 7.0.9, as well as the 7.1.x series before 7.3.4, the 7.4.x series before 7.4.3, and release candidate 8.0rc1. Patches have been released in versions 7.0.9, 7.3.4, 7.4.3, and 8.0rc2. No workarounds are available, making an upgrade imperative for all affected deployments.
DailyCVE Form:
Platform: Wagtail CMS
Version: <7.0.9, 7.1-7.3.3, 7.4-7.4.2, 8.0rc1
Vulnerability: Authorization Bypass (Copy)
Severity: Moderate (CVSS 6.5)
Date: August 20, 2026
Prediction: Patch already released
What Undercode Say:
Analytics:
The vulnerability stems from a missing permission check on the source snippet instance within the copy view handler. The Wagtail admin uses Django’s permission backend, where `add` permission is checked for the destination (new snippet creation) but `view` or `change` permissions are not enforced for the source object. The copy endpoint likely invokes a `get_object_or_404` query without filtering by user-accessible snippets, then clones the instance without verifying read access.
To verify whether your deployment is vulnerable, inspect the snippet copy URL pattern:
/admin/snippets/<app_label>/<model_name>/<pk>/copy/
If a user with only `add` permission can access this endpoint with any valid `pk` and receive a pre-filled copy form, the system is vulnerable.
Exploit: (Educational Purposes!)
Step 1 – Identify a snippet model where the user has “add” but not “view” permission.
Step 2 – Enumerate snippet primary keys (predictable integers) via the admin index or by brute force.
Step 3 – Access the copy endpoint:
GET /admin/snippets/myapp/mysnippet/123/copy/
Step 4 – Submit the copy form to create a duplicate. The response will display all fields from the source snippet, revealing its contents.
Python proof-of-concept (authenticated session required):
import requests
session = requests.Session()
Login to Wagtail admin first
snippet_id = 123
url = f"https://target.com/admin/snippets/myapp/mysnippet/{snippet_id}/copy/"
response = session.get(url)
Parse response HTML for field values
Protection:
- Upgrade to Wagtail 7.0.9, 7.3.4, 7.4.3, or 8.0rc2 immediately.
- If unable to upgrade, override the snippet copy view to enforce `view` permission on the source instance via a custom `ModelAdmin` or by monkey-patching the `copy` method.
- Audit existing users with only “add” permissions and restrict snippet model access where possible.
- Monitor admin logs for unusual copy operations on snippet models.
Impact:
An authenticated CMS user with only snippet creation privileges can view the contents of any existing snippet instance, including those they are explicitly denied access to. This leads to unauthorized disclosure of sensitive configuration data, personal information, or internal business logic stored as snippets. The attacker cannot modify or delete snippets, but the confidentiality breach can facilitate further attacks or data exfiltration. The vulnerability does not affect public-facing site visitors; exploitation requires valid admin credentials.
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Sources:
Reported By: github.com
Extra Source Hub:
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