CVE-2025-13859

AffiliateX 1.0.0 - 1.3.9.3 - Authenticated (Subscriber+) Missing Authorization to Stored Cross-Site Scripting via save_customization_settings

2026-01-15 00:30
kr0d

Strategic Overview

At a glance

CVE-2025-13859 is a medium-severity Missing Authorization vulnerability in the AffiliateX WordPress plugin, affecting versions 1.0.0 – 1.3.9.3. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 1.4.0; sites on affected versions should update now. Disclosed January 2026, reported by kr0d.

Vulnerability Overview

The AffiliateX – Amazon Affiliate Plugin plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the save_customization_settings AJAX action in versions 1.0.0 to 1.3.9.3. This makes it possible for authenticated attackers, with Subscriber-level access and above, to store arbitrary JavaScript that executes whenever an AffiliateX block renders on the site.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.

CWE-862: Missing Authorization

Reaching this weakness in AffiliateX 1.0.0 – 1.3.9.3 takes an account at Subscriber level or above. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.

Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For AffiliateX the fix is 1.4.0: builds 1.0.0 – 1.3.9.3 are affected, anything from 1.4.0 onward is not.

Remediation

Update to version 1.4.0, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: AffiliateX 1.4.0 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

Other vulnerabilities in AffiliateX – Amazon Affiliate Plugin, Product Boxes, Comparison Tables & Affiliate Link Tracking

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