CVE-2026-10513
Received Received - Intake

Stored XSS in Webmention WordPress Plugin

Publication date: 2026-06-30

Last updated on: 2026-06-30

Assigner: Wordfence

Description
The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 5.8.0 via parser-derived 'avatar' and 'url' author metadata. This is due to insufficient input sanitization and output escaping on user-supplied MF2 author properties processed by the unauthenticated webmention REST endpoint and rendered directly into HTML 'value' attributes by the edit-comment-form template without esc_attr() or esc_url(). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a privileged user (moderator or administrator) opens the affected comment edit screen.

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Meta Information

Published
2026-06-30
Last Modified
2026-06-30
Generated
2026-07-01
AI Q&A
2026-06-30
EPSS Evaluated
N/A
NVD
CVE-2026-10513
EUVD
EUVD-2026-40376

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wordfence webmention_plugin to 5.8.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
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.

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Executive Summary

The Webmention plugin for WordPress versions up to and including 5.8.0 contains a Stored Cross-Site Scripting (XSS) vulnerability. This occurs because the plugin does not properly sanitize or escape user-supplied author metadata, specifically the 'avatar' and 'url' fields derived from the parser. These fields are processed by an unauthenticated webmention REST endpoint and then rendered directly into HTML 'value' attributes in the comment edit form without using proper escaping functions like esc_attr() or esc_url(). As a result, an unauthenticated attacker can inject malicious scripts that execute when a privileged user, such as a moderator or administrator, opens the affected comment edit screen.

Impact Analysis

This vulnerability allows unauthenticated attackers to inject arbitrary web scripts into pages viewed by privileged users. When a moderator or administrator opens the comment edit screen, the malicious scripts execute in their browser context. This can lead to unauthorized actions performed with the privileges of the targeted user, potentially compromising site security, leaking sensitive information, or enabling further attacks such as privilege escalation or site takeover.

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