GHSA-8jj7-4v57-frf5: SQL Injection
Summary The moveplugin admin endpoint does not prevent a plugin from being reparented under itself or one of its own descendants. Doing so creates a cycle in the plugin tree, after which the recursive descendant/ancestor SQL queries loop without terminating, stalling the request worker.
Details moveplugin (in cms/admin/placeholderadmin.py) accepts a pluginparent POST parameter and, for an in-placeholder move, sets the plugin's parent to the target without any cycle/ancestor check. If the target parent is a descendant of the moved plugin, the resulting parentid graph contains a cycle.
Descendant and ancestor traversal is implemented with WITH RECURSIVE CTEs (getdescendantscte / getancestorscte in cms/models/pluginmodel.py) that have no cycle clause or depth limit. On a cyclic tree these recurse indefinitely (PostgreSQL/SQLite) or error at the recursion limit (MySQL). getdescendants() is invoked while building the move response and on subsequent operations on the affected subtree.
Impact An authenticated staff user with permission to change plugins in at least one placeholder can corrupt that placeholder's plugin tree, causing requests that traverse it (rendering, copy, delete) to hang and consume application workers (denial of service). The tree is also left in a corrupted state.
Requires CMSPERMISSION/plugin-change permission on a placeholder.
Patches Fixed in 5.0.8: moveplugin now rejects (HTTP 400) any move that would place a plugin inside itself or one of its descendants, before any tree mutation or traversal.
Workarounds None. Upgrade is recommended.
Credits Reported by the security team at the University of Sydney ([@reporter]).
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
pip/django-cmsto a version that resolves this vulnerability.Fixed in 5.0.8 - Upgrade
Upgrade
cmsto a version that resolves this vulnerability.Fixed in 5.0.8 - Compensating control
Restrict use of the `move_plugin` admin endpoint to trusted staff only, since it requires `CMS_PERMISSION`/plugin-change permission and the endpoint otherwise allows reparenting a plugin under itself or one of its own descendants.
Event History
Frequently Asked Questions
Who can trigger this issue?
An authenticated staff user who has permission to change plugins in at least one placeholder can trigger it. No user interaction is required.
What action causes the plugin tree to become corrupted?
The user must submit an in-placeholder move through the move_plugin admin endpoint with plugin_parent set to the moved plugin itself or one of that plugin's descendants. This creates a cycle in the parent_id graph.
What operational behavior indicates a placeholder may already be affected?
Requests that build a move response or perform later operations on the affected subtree may stall because descendant or ancestor traversal does not terminate. On MySQL, traversal may instead fail when the database recursion limit is reached.