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

mediumCVSS 6.4CVE-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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 6.4
Published: 2026-07-03
Last updated: 2026-07-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-9626

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-96260.23% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 14% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-9626	coverage & exploitation status	NVD · CVE.org

Recent advisories for JSON API User

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumGHSA-pjhx-3c3w-9v23: API Platform Core vulnerable to cross-user attribute leak in JSON:API and HAL item normal…ghsa · 2026-07-10
highCVE-2026-59712: Leantime's Users::getUser method in the JSON-RPC API lacks proper authorization checks, allowi…nvd · 2026-07-06

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

Details

Exploitation outlook

Referenced CVEs

Recent advisories for JSON API User

More from NVD Recent CVEs