This module adds a tab for sufficiently permissioned users. The tab shows all revisions like standard Drupal but it also allows pretty viewing of all added/changed/deleted words between revisions.
The module doesn't sufficiently check revision access before rendering a diff report for 1) nodes or 2) general entities that support diff.
This vulnerability is mitigated by the fact that an attacker must have a role with the permission from the general node permission to "view all revisions", one of the more specific node type permissions, "view %bundle revisions" or the equivalent for other general entity types.
Install the latest version:
- If you use the Diff module for Drupal, upgrade to Diff 8.x-1.8
- Greg Knaddison of the Drupal Security Team
- Juraj Nemec of the Drupal Security Team