CVE-2026-9626

Description

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.

CVSS v3.1 Score

6.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://plugins.trac.wordpress.org/browser/json-api-user/tags/4.1.0/controllers/User.php#L1007 https://plugins.trac.wordpress.org/browser/json-api-user/tags/4.1.0/controllers/User.php#L979 https://plugins.trac.wordpress.org/browser/json-api-user/tags/4.1.0/controllers/User.php#L995 https://plugins.trac.wordpress.org/changeset/3576431/json-api-user/trunk/controllers/User.php https://plugins.trac.wordpress.org/changeset?old_path=%2Fjson-api-user/tags/4.1.0&new_path=%2Fjson-api-user/tags/4.1.2 https://www.wordfence.com/threat-intel/vulnerabilities/id/c41b0370-2881-4053-98b1-9c70251a3b63?source=cve

Frequently Asked Questions

What is CVE-2026-9626? +

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. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2026-9626? +

CVE-2026-9626 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-9626? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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