WordPress Core < 6.3.2 – Authenticated (Subscriber+) Arbitrary Shortcode Execution via parse-media-shortcode
Strategic Overview
- Status
- Patched in 4.1.39
- Affected Core
- WordPress 6.3
- Affected Version
4.1.38 – 6.3.1 · 23 branches- CVSS
- 5.4Medium
- Weakness type
- CWE-20 · Improper Input Validation
- CVE
CVE pending
At a glance
This record tracks a medium-severity Improper Input Validation vulnerability in the WordPress 6.3 WordPress release line, affecting 4.1.38 – 6.3.1 · 23 branches. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 4.1.39; sites on affected versions should update now. Disclosed October 2023, reported by James Golovich.
Vulnerability Overview
WordPress Core is vulnerable to arbitrary shortcode execution in versions up to, and including, 6.3.1 due to a lack of input validation on the 'shortcode' parameter in the parse_media_shortcode AJAX function. This allows authenticated attackers, with subscriber-level privileges and above, to execute arbitrary shortcodes.
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-20: Improper Input Validation
WordPress 6.3 4.1.38 – 6.3.1 · 23 branches carries this weakness at shortcode, and reaching it takes an account at Subscriber level or above. Improper input validation means the application accepts input without confirming it has the form, type or range the code downstream assumes.
The concrete impact depends on where the unvalidated value lands, which is why records in this class range from cosmetic bugs to full compromise. For WordPress 6.3 the fix is 4.1.39: builds 4.1.38 – 6.3.1 · 23 branches are affected, anything from 4.1.39 onward is not.
Remediation
Update to one of the following versions, or a newer patched version: 4.1.39, 4.2.36, 4.3.32, 4.4.31, 4.5.30, 4.6.27, 4.7.27, 4.8.23, 4.9.24, 5.0.20, 5.1.17, 5.2.19, 5.3.16, 5.4.14, 5.5.13, 5.6.12, 5.7.10, 5.8.8, 5.9.8, 6.0.6, 6.1.4, 6.2.3, 6.3.2
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: updating to 4.1.39 is the step that ends it.
- Firewall
- Alerts
External References
Related records
Same weakness class
- 6.3CVE-2011-3125: WordPress Core < 3.1.3 Security Hardening
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CVE-2016-9263 - 4.6CVE-2013-2204: WordPress Core <= 3.5.1 Content-Spoofing Attacks
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Other vulnerabilities in WordPress 6.3
- 9.8CVE-2026-63030: WordPress Core 6.9 - 7.0.1 Remote Code Execution
CVE-2026-63030 - 9.8CVE-2024-31211: WordPress Core 6.4.0 - 6.4.1 RCE POP Chain
CVE-2024-31211 - 9.8WordPress Core < 6.0.3 SQL Injection via WP_Date_Query
- 9.8CVE-2021-29476: WordPress Core < 5.5.3 PHP Object Injection Gadget
CVE-2021-29476 - 9.8CVE-2017-16510: WordPress Core SQL Injection
CVE-2017-16510 - 9.8CVE-2017-14723: WordPress Core < 4.8.2 SQL Injection
CVE-2017-14723 - 9.8CVE-2007-6013: WordPress Core 1.5 - 2.3.1 Authorization Bypass
CVE-2007-6013 - 9.8CVE-2007-6318: WordPress Core < 2.3.2 SQL Injection
CVE-2007-6318
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