CVE-2025-53348: Kalium Authorization Bypass Vulnerability

CVE-2025-53348 Overview

CVE-2025-53348 is a missing authorization vulnerability affecting the Laborator Kalium WordPress theme through version 3.18.3. The flaw stems from incorrectly configured access control security levels, allowing unauthenticated attackers to interact with functionality that should require authorization. The issue is tracked under CWE-862: Missing Authorization.

The vulnerability affects sites running the Kalium theme, a commercial WordPress theme widely deployed for portfolio and business sites. Exploitation occurs over the network without user interaction or privileges, but the integrity impact is limited to low.

Critical Impact
Unauthenticated network-based attackers can exploit incorrectly configured access controls in the Kalium theme to interact with protected functionality, resulting in limited integrity impact.

Affected Products

Laborator Kalium WordPress Theme versions up to and including 3.18.3
WordPress installations with the Kalium theme active
Any site inheriting Kalium theme access control configurations

Discovery Timeline

2025-09-09 - CVE-2025-53348 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-53348

Vulnerability Analysis

The Kalium theme exposes functionality that lacks proper authorization checks before executing sensitive operations. When a request reaches a protected handler, the theme fails to verify whether the caller possesses the required capability or role. This allows unauthenticated requests to reach functionality that assumes the caller is authorized.

The missing authorization pattern typically appears in AJAX endpoints, form handlers, or REST routes registered by the theme. Without a capability check such as current_user_can() or a valid nonce verification via check_ajax_referer(), the handler processes attacker-supplied input.

The scope remains unchanged, and confidentiality and availability are not impacted based on the CVSS vector. The integrity impact is limited, meaning an attacker can modify a subset of data but cannot compromise the entire application state.

Root Cause

The root cause is an incorrectly configured access control layer inside the Kalium theme. The theme registers handlers that should be restricted to authenticated users or administrators but omits capability verification. This aligns with CWE-862, where the software does not perform an authorization check when an actor attempts to access a resource.

Attack Vector

Exploitation requires only network access to the target WordPress site. An attacker sends a crafted HTTP request to the vulnerable endpoint exposed by the Kalium theme. Because no authentication or user interaction is required, the attack can be automated and delivered at scale against sites running vulnerable versions.

For technical details on the specific vulnerable endpoint, refer to the Patchstack Kalium Theme Advisory.

Detection Methods for CVE-2025-53348

Indicators of Compromise

Unauthenticated HTTP POST requests to Kalium theme AJAX endpoints under /wp-admin/admin-ajax.php with theme-specific action parameters
Unexpected modifications to theme options, settings, or content authored by unauthenticated sessions
Anomalous traffic spikes targeting /wp-content/themes/kalium/ paths

Detection Strategies

Inspect WordPress access logs for requests to Kalium-specific action handlers originating from unauthenticated sessions
Correlate theme option changes in the WordPress database with the absence of an authenticated admin session
Deploy a WordPress security plugin or web application firewall (WAF) rule to alert on unauthenticated requests to theme handlers

Monitoring Recommendations

Enable WordPress audit logging to capture changes to theme settings, user roles, and posts
Monitor wp_options, wp_postmeta, and theme customizer tables for unexpected writes
Alert on repeated failed or anomalous requests to admin-ajax.php with Kalium-related actions

How to Mitigate CVE-2025-53348

Immediate Actions Required

Update the Laborator Kalium theme to a version later than 3.18.3 once the vendor releases a fix
Audit WordPress installations to inventory the Kalium theme version in use
Restrict access to /wp-admin/admin-ajax.php from untrusted networks where feasible

Patch Information

At the time of this advisory, the vulnerability affects Kalium versions up to and including 3.18.3. Site administrators should consult the Patchstack Kalium Theme Advisory and the vendor changelog for the fixed release. Apply the update through the WordPress admin dashboard or via SFTP once available.

Workarounds

Deploy a web application firewall (WAF) rule blocking unauthenticated requests to Kalium theme AJAX actions
Temporarily deactivate the Kalium theme and switch to a default WordPress theme if patching is not immediately possible
Use a virtual patching solution such as Patchstack to shield the vulnerable endpoint until the vendor fix is applied

bash

# Example WAF rule (ModSecurity) to block unauthenticated Kalium AJAX actions
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
    "chain,phase:2,deny,status:403,id:1000053348,msg:'Block unauthenticated Kalium theme AJAX'"
SecRule ARGS:action "@rx ^kalium_" \
    "chain"
SecRule &REQUEST_COOKIES:/wordpress_logged_in_/ "@eq 0"