CVE-2026-58589: Flowdrop Auth Bypass Vulnerability

CVE-2026-58589 Overview

CVE-2026-58589 is a Missing Authorization vulnerability [CWE-862] in the Drupal FlowDrop contributed module. The flaw allows authenticated users to perform forceful browsing against resources that should be access-restricted. Affected versions include FlowDrop 0.0.0 through 1.6.0.

The issue enables low-privileged users to access functionality or data outside their intended authorization scope. Exploitation requires network access and valid low-level credentials, with no user interaction. The vendor published a security advisory on drupal.org tracking this issue.

Critical Impact
Authenticated attackers can bypass access controls in FlowDrop to reach resources or actions restricted to higher-privileged users, exposing limited confidentiality and integrity impacts.

Affected Products

Drupal FlowDrop module versions 0.0.0 through 1.6.0
Drupal sites running the flowdrop_project:flowdrop contributed module
Any Drupal deployment where FlowDrop is installed and enabled

Discovery Timeline

2026-07-10 - CVE-2026-58589 published to NVD
2026-07-14 - Last updated in NVD database

Technical Details for CVE-2026-58589

Vulnerability Analysis

The vulnerability is a Missing Authorization weakness in the FlowDrop Drupal module. FlowDrop exposes routes or operations that do not verify whether the requesting user holds the permissions required to access them. As a result, authenticated users can invoke functionality intended for other roles by directly requesting the underlying URLs, a pattern known as forceful browsing.

The attack requires network reachability to the Drupal site and a valid low-privileged account. No user interaction is needed, and exploitation complexity is low. Successful abuse yields limited confidentiality and integrity impact, without affecting availability.

Because the flaw resides in the module's access control layer, standard Drupal permission checks or route access callbacks are either missing or improperly evaluated. Consult the Drupal Security Advisory for module-specific technical details.

Root Cause

The root cause is the absence of authorization checks on one or more FlowDrop routes, controllers, or entity operations. Drupal modules must define _permission or _custom_access requirements on routing entries and validate user permissions before returning data or executing actions. FlowDrop versions up to 1.6.0 omit or incorrectly implement these checks.

Attack Vector

An authenticated attacker with any FlowDrop-adjacent role sends direct HTTP requests to protected FlowDrop endpoints. Because the module does not verify authorization, the server processes the request and returns data or performs actions the user should not access. The attack is fully network-based and does not depend on social engineering or client-side interaction.

No public proof-of-concept has been released, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. EPSS data reports a low predicted exploitation probability.

Detection Methods for CVE-2026-58589

Indicators of Compromise

Authenticated HTTP requests to FlowDrop routes originating from user roles that lack legitimate access to the target functionality.
Unexpected 200 OK responses on FlowDrop administrative or configuration paths for standard authenticated users.
Access log entries showing enumeration of FlowDrop URL patterns by a single session or IP.

Detection Strategies

Review Drupal watchdog logs and web server access logs for requests to FlowDrop paths grouped by user role and response code.
Correlate uid values in Drupal session logs against the FlowDrop endpoints they successfully accessed to identify permission mismatches.
Deploy web application firewall rules that alert on authenticated access to FlowDrop administrative routes from non-privileged accounts.

Monitoring Recommendations

Enable verbose logging for the FlowDrop module and forward Drupal logs to a centralized SIEM or data lake for correlation.
Baseline normal FlowDrop usage patterns per role and alert on deviations, particularly for accounts with only basic privileges.
Monitor for sequential URL access patterns indicative of forceful browsing against /flowdrop/* paths.

How to Mitigate CVE-2026-58589

Immediate Actions Required

Upgrade FlowDrop to a fixed version above 1.6.0 as indicated in the Drupal Security Advisory.
Audit existing FlowDrop-related user accounts and revoke unnecessary authenticated access while the patch is being deployed.
Review Drupal watchdog and access logs for prior evidence of unauthorized access to FlowDrop endpoints.

Patch Information

The Drupal Security Team published advisory SA-CONTRIB-2026-067 with remediation guidance for the FlowDrop module. Administrators should update to the fixed release listed in the advisory using either the Drupal UI, drush, or Composer-based workflows. Refer to the Drupal Security Advisory for the exact fixed version identifier.

Workarounds

If patching cannot occur immediately, disable the FlowDrop module via drush pm:uninstall flowdrop or the Drupal Extend UI.
Restrict access to FlowDrop routes at the web server or reverse proxy layer by requiring elevated authentication for the module's URL paths.
Remove the authenticated user role from any FlowDrop-specific permissions and grant them only to trusted roles until the upgrade is applied.

bash

# Update FlowDrop using Composer and clear caches
composer update drupal/flowdrop --with-dependencies
drush updatedb -y
drush cache:rebuild

# Alternative: disable the module until patched
drush pm:uninstall flowdrop -y