CVE-2026-8438

All-In-One Security (AIOS) <= 5.4.7 - Unauthenticated Stored Cross-Site Scripting via REST API Request Path

2026-06-05 11:51
Dmitrii Ignatyev

Strategic Overview

Status
Patched in 5.4.8
Affected Version
<= 5.4.7
CVSS
7.2High
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-8438
View all All-In-One Security (AIOS) – Security and Firewall vulnerabilities

At a glance

CVE-2026-8438 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the All-In-One Security (AIOS) WordPress plugin, affecting versions <= 5.4.7. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 5.4.8; sites on affected versions should update now. Disclosed June 2026, reported by Dmitrii Ignatyev.

Vulnerability Overview

The All-In-One Security (AIOS) – Security and Firewall plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.4.7. This is due to insufficient input sanitization in the get_rest_route() function and missing output escaping in the column_default() method of the debug log list table. When the 'Disable REST API for non-logged in users' feature (aiowps_disallow_unauthorized_rest_requests) is enabled alongside debug logging (aiowps_enable_debug), an unauthenticated attacker can embed arbitrary HTML or JavaScript in the REST request path. The path is retrieved via urldecode($_SERVER['REQUEST_URI']), which decodes URL-encoded payloads into literal HTML characters. This decoded, unsanitized value is concatenated directly into a debug log message and stored in the database. When an administrator navigates to the AIOS Dashboard Debug Logs page, the column_default() method returns the raw database value without escaping, and the parent list table echoes it directly, causing JavaScript execution in the administrator's browser session. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute when an administrator views the debug log page, enabling nonce theft, privileged AJAX/REST actions, and potential full site compromise.

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 privileges on the target site, and no interaction from a victim user.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

All-In-One Security (AIOS) <= 5.4.7 carries this weakness at REQUEST_URI, and reaching it takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For All-In-One Security (AIOS) the fix is 5.4.8: builds <= 5.4.7 are affected, anything from 5.4.8 onward is not.

Remediation

Update to version 5.4.8, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: All-In-One Security (AIOS) 5.4.8 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Login Security
  • Alerts

External References

Related records

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