CVE-2026-73477 Overview
CVE-2026-73477 is an Incorrect Authorization vulnerability [CWE-863] in the Drupal Quick Tabs contributed module. The flaw allows Forceful Browsing, meaning unauthenticated attackers can access resources by requesting URLs directly without passing through the intended authorization checks. The issue affects all Quick Tabs versions from 0.0.0 through 4.3.1. Successful exploitation exposes limited confidential information but does not affect integrity or availability. The vulnerability is remotely exploitable over the network with no authentication or user interaction required.
Critical Impact
Unauthenticated remote attackers can bypass authorization controls in Drupal Quick Tabs and access content that should be restricted, resulting in disclosure of limited confidential data.
Affected Products
- Drupal Quick Tabs module versions 0.0.0 through 4.3.1
- Drupal sites with the Quick Tabs contributed module enabled
- Any Drupal deployment relying on Quick Tabs to render access-controlled tabbed content
Discovery Timeline
- 2026-09-02 - CVE-2026-73477 published to NVD
- 2026-09-02 - Last updated in NVD database
- Refer to the Drupal Security Advisory for the vendor disclosure
Technical Details for CVE-2026-73477
Vulnerability Analysis
Quick Tabs is a Drupal contributed module that renders multiple pieces of content, such as views, blocks, and nodes, as tabbed interfaces on a page. The module fails to consistently enforce authorization on the resources it exposes through its tab-loading endpoints. As a result, an attacker who guesses or discovers a valid URL or identifier can retrieve content that the site's access control policies should have blocked.
The vulnerability is classified as Incorrect Authorization [CWE-863]. It represents a Broken Access Control weakness where the application performs an authorization check that is either missing, incomplete, or incorrectly evaluated for the requested resource. The scope of exposure is limited to confidentiality; the flaw does not permit data modification or denial of service.
Root Cause
The root cause is missing or incorrect access control logic in the Quick Tabs code paths that load tab contents. When the module renders or fetches a referenced entity for a tab, it does not re-validate that the current session has permission to view that entity. This produces the Forceful Browsing condition, where direct requests to internal endpoints or crafted parameters return protected data.
Attack Vector
Exploitation occurs over the network with no privileges and no user interaction. An attacker sends crafted HTTP requests to a vulnerable Drupal site that has Quick Tabs enabled. By supplying identifiers that reference restricted content, the attacker retrieves data through the module's rendering path rather than through the standard, access-checked page controller. No exploit code, public proof of concept, or CISA KEV listing is currently associated with this CVE.
No verified exploit code is available. Refer to the Drupal Security Advisory for vendor-provided technical details.
Detection Methods for CVE-2026-73477
Indicators of Compromise
- Unexpected HTTP requests to Quick Tabs endpoints or AJAX callbacks from unauthenticated sessions retrieving entity identifiers outside a user's normal scope.
- Web server access logs showing enumeration patterns against Quick Tabs routes with varying node, view, or block IDs.
- Application logs indicating rendering of restricted entities in responses served to anonymous or low-privilege sessions.
Detection Strategies
- Review Drupal watchdog and access logs for anonymous requests that successfully render entities marked as restricted.
- Correlate spikes in Quick Tabs endpoint traffic with responses containing content types that should require authentication.
- Run authenticated and unauthenticated crawls against staging environments to identify tabs that leak protected entities.
Monitoring Recommendations
- Enable verbose logging on the Quick Tabs module and forward Drupal logs to a centralized analytics platform for anomaly review.
- Alert on high-rate ID enumeration against Quick Tabs paths, which is characteristic of forceful browsing attempts.
- Monitor for changes to the module version and confirm that upgrades are applied across all Drupal environments.
How to Mitigate CVE-2026-73477
Immediate Actions Required
- Upgrade the Drupal Quick Tabs module to a version later than 4.3.1 as directed by the Drupal Security Advisory.
- Inventory all Drupal sites in the environment and identify those with Quick Tabs enabled to prioritize patching.
- Audit content rendered through Quick Tabs to determine whether any restricted entities were exposed prior to patching.
Patch Information
The vendor has published guidance in the Drupal Security Advisory SA-CONTRIB-2026-099. Site operators should apply the fixed release of the Quick Tabs module referenced in that advisory and clear Drupal caches after the upgrade to ensure the corrected authorization logic is loaded.
Workarounds
- Temporarily disable and uninstall the Quick Tabs module on affected sites if upgrading is not immediately possible.
- Restrict access to Quick Tabs endpoints at the web server or reverse proxy layer to authenticated sessions only.
- Remove Quick Tabs instances that reference sensitive or access-controlled entities until the patched version is deployed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.