pfefferle Webmention Plugin up to 5.10.1 on WordPress Webmention Processing Receiver::process cross site scripting

Summaryinfo

A vulnerability classified as problematic was found in pfefferle Webmention Plugin up to 5.10.1. Affected by this vulnerability is the function Receiver::process of the component Webmention Processing. Such manipulation leads to cross site scripting. This vulnerability is documented as CVE-2026-111109. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in pfefferle Webmention Plugin up to 5.10.1. It has been rated as problematic. Affected by this issue is the function Receiver::process of the component Webmention Processing. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Open Graph og:title meta tag of a webmention source URL in versions up to, and including, 5.10.1. This is due to insufficient input sanitization: Meta::add_properties() maps og:title to the Item::name property, but Item has no concrete set_name() method, so Item::__call() stores the value raw while sibling set_content()/set_summary() paths route through webmention_sanitize_html(); Item::get_content() then falls back to the raw name when content and summary are empty, and Receiver::process() explicitly removes the core wp_filter_kses / wp_filter_post_kses hooks on pre_comment_content before calling wp_new_comment(), so the payload is persisted to comment_content as-is. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page, after an administrator approves the resulting pending webmention comment. Successful exploitation additionally requires an action by an administrator — the attacker cannot trigger the vulnerability on their own.

The advisory is available at wordfence.com. This vulnerability is handled as CVE-2026-111109 since 10/15/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• WordPress Plugin

Vendor

• pfefferle

Name

• Webmention Plugin

Version

• 5.10.0
• 5.10.1

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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