CVE-2026-57729: Flatsome Theme Auth Bypass Vulnerability

CVE-2026-57729 Overview

CVE-2026-57729 is a Missing Authorization vulnerability [CWE-862] affecting the UX-themes Flatsome WordPress theme through version 3.20.5. The flaw stems from incorrectly configured access control security levels, allowing unauthenticated attackers to interact with functionality that should require authorization. The issue is exploitable over the network without user interaction or privileges, and it impacts the confidentiality of data served by affected sites. Flatsome is a widely deployed commercial WooCommerce theme, which broadens the potential attack surface across e-commerce deployments.

Critical Impact
Unauthenticated network attackers can bypass access controls in Flatsome <= 3.20.5 and access restricted theme functionality, resulting in confidentiality impact on affected WordPress sites.

Affected Products

UX-themes Flatsome WordPress theme versions up to and including 3.20.5
WordPress sites running Flatsome with WooCommerce integrations
Any deployment relying on Flatsome theme access control for restricted endpoints

Discovery Timeline

2026-07-13 - CVE-2026-57729 published to NVD
2026-07-13 - Last updated in NVD database

Technical Details for CVE-2026-57729

Vulnerability Analysis

The vulnerability is a Broken Access Control weakness classified under [CWE-862] Missing Authorization. Flatsome exposes functionality that fails to verify whether the requesting user holds the required capability or role before executing sensitive operations. Because the theme does not enforce authorization checks on affected handlers, an unauthenticated attacker can invoke these endpoints directly. The vulnerability is reachable over the network with low attack complexity and no user interaction. The confidentiality impact is high, while integrity and availability are not affected, indicating that the flaw primarily exposes protected data rather than modifying site state.

Root Cause

The root cause is the absence of capability or nonce validation on one or more Flatsome theme handlers. In WordPress themes, sensitive actions should be gated by current_user_can() checks and, where applicable, check_ajax_referer() or wp_verify_nonce() calls. Flatsome versions up to 3.20.5 register handlers that skip these controls, treating access as implicitly authorized. See the Patchstack Flatsome Theme Vulnerability advisory for details on the affected code paths.

Attack Vector

An unauthenticated attacker sends crafted HTTP requests to the affected Flatsome endpoints on a vulnerable WordPress site. Because no privileges or user interaction are required, exploitation can be automated at scale against internet-facing WordPress deployments. Successful requests return data that should be restricted to authorized users, resulting in information disclosure.

No verified public proof-of-concept code is available at the time of publication. Refer to the vendor advisory for technical specifics.

Detection Methods for CVE-2026-57729

Indicators of Compromise

Anomalous unauthenticated HTTP requests to Flatsome theme handlers under /wp-content/themes/flatsome/ or admin-ajax.php referencing Flatsome-specific actions
Requests to WordPress AJAX or REST endpoints without valid session cookies or nonce parameters
Unexpected outbound data volume from WordPress hosts running Flatsome <= 3.20.5

Detection Strategies

Inventory WordPress installations and enumerate the Flatsome theme version from style.css to identify hosts running <= 3.20.5
Enable WordPress debug logging and web server access logs to capture calls to Flatsome AJAX actions from unauthenticated sessions
Deploy a Web Application Firewall (WAF) rule to flag requests to Flatsome endpoints lacking authentication cookies or nonces

Monitoring Recommendations

Alert on repeated admin-ajax.php requests with Flatsome-specific action parameters originating from a single IP over short time windows
Correlate WordPress access logs with authentication events to identify data access without a corresponding login
Track theme version drift across managed WordPress fleets and alert when Flatsome remains at 3.20.5 or earlier after patch release

How to Mitigate CVE-2026-57729

Immediate Actions Required

Update Flatsome to a version later than 3.20.5 as soon as the vendor publishes a patched release
Audit WordPress user accounts and API tokens for signs of unauthorized data access
Restrict administrative and AJAX endpoints behind a WAF with authenticated-only rules where feasible

Patch Information

Refer to the Patchstack Flatsome Theme Vulnerability advisory for the fixed version and upgrade guidance. Apply the vendor-supplied update through the WordPress admin dashboard or by replacing the theme files manually.

Workarounds

Deploy a virtual patch via a WAF or Patchstack mitigation rule to block unauthenticated access to the vulnerable Flatsome handlers
Temporarily disable non-essential Flatsome features that expose the affected endpoints until a patched release is applied
Enforce IP allow-listing on /wp-admin/ and admin-ajax.php where operationally feasible to limit exposure

bash

# Identify Flatsome theme version on a WordPress host
grep -E "^Version:" /var/www/html/wp-content/themes/flatsome/style.css

# Example nginx rule to block unauthenticated admin-ajax calls to Flatsome actions
location = /wp-admin/admin-ajax.php {
    if ($http_cookie !~* "wordpress_logged_in_") {
        return 403;
    }
}