MW WP Form <= 5.1.3 - Authenticated (Editor+) Stored Cross-Site Scripting via 'memo' Parameter
Strategic Overview
- Status
- Patched in 5.1.4
- Affected Plugin
- MW WP Form
- Affected Version
<= 5.1.3- CVSS
- 4.4Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2026-8853
At a glance
CVE-2026-8853 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the MW WP Form WordPress plugin, affecting versions <= 5.1.3. It carries a CVSS score of 4.4 (reachable over the network). Exploitation requires an authenticated account at Editor level or above. The issue is fixed in version 5.1.4; sites on affected versions should update now. Disclosed June 2026, reported by Sérgio Charruadas (itzvenom).
Vulnerability Overview
The MW WP Form plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'memo' parameter in all versions up to, and including, 5.1.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with editor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Because the memo value is stored via update_post_meta() rather than wp_insert_post(), WordPress's built-in kses and unfiltered_html protections do not apply, allowing attackers to break out of the textarea element via injected closing tags regardless of role-based content filtering.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
MW WP Form <= 5.1.3 carries this weakness at memo, and reaching it takes an account at Editor 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 MW WP Form the fix is 5.1.4: builds <= 5.1.3 are affected, anything from 5.1.4 onward is not.
Remediation
Update to version 5.1.4, or a newer patched version
How does WordSec protect against this?
An attacker needs Editor 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: MW WP Form 5.1.4 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in MW WP Form
- 9.8CVE-2023-6316: MW WP Form <= 5.0.1 Arbitrary File Upload
CVE-2023-6316 - 8.1CVE-2026-5436: MW WP Form <= 5.1.1 Arbitrary File Move
CVE-2026-5436 - 8.1CVE-2026-4347: MW WP Form <= 5.1.0 Arbitrary File Move
CVE-2026-4347 - 7.5CVE-2023-6559: MW WP Form Improper Limitation of File Name
CVE-2023-6559 - 5.3CVE-2026-6206: MW WP Form IDOR
CVE-2026-6206 - 5.3CVE-2023-46206: MW WP Form <= 4.4.5 Missing Authorization
CVE-2023-46206 - 5.3CVE-2023-28409: MW WP Form <= 4.4.2 Directory Traversal
CVE-2023-28409
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