JSON API User <= 4.1.0 - Authenticated (Subscriber+) Stored Cross-Site Scripting via 'content' Parameter
Strategic Overview
- Status
- Patched in 4.1.2
- Affected Plugin
- JSON API User
- Affected Version
<= 4.1.0- CVSS
- 6.4Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2026-9626
At a glance
CVE-2026-9626 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the JSON API User WordPress plugin, affecting versions <= 4.1.0. 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 4.1.2; sites on affected versions should update now. Disclosed July 2026, reported by Yat.
Vulnerability Overview
The JSON API User plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'content' parameter of the post_comment API endpoint in versions up to, and including, 4.1.0 This is due to insufficient input sanitization in the post_comment() function, which passes the attacker-controlled comment_content value directly to wp_insert_comment() without applying any HTML sanitization, and additionally allows the caller to set comment_approved=1 to self-approve the comment and bypass moderation. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
JSON API User <= 4.1.0 carries this weakness at content, and reaching it takes an account at Subscriber level or above. 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 JSON API User the fix is 4.1.2: builds <= 4.1.0 are affected, anything from 4.1.2 onward is not.
Remediation
Update to version 4.1.2, or a newer patched version
How does WordSec protect against this?
An attacker needs Subscriber access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: JSON API User 4.1.2 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Other vulnerabilities in JSON API User
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