or JSON-LD name/headline) in all versions from 5.1.2 up to, and including, 5.10.1, due to insufficient input sanitization. Unlike the content and summary, the entry name was not sanitized, and it is used as the comment content when the source page has no content or summary, while the plugin disables WordPress's comment content filtering when it stores a Webmention. This makes it possible for unauthenticated attackers who send a Webmention from a page they control to inject arbitrary web scripts in pages that execute whenever a user accesses the page where the Webmention is displayed. ## References - https://wpsec.com/vuln/WPSEC-2026-1121/ - https://plugins.svn.wordpress.org/webmention/tags/5.10.2/ - https://wordpress.org/plugins/webmention/ Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1121/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.

# Webmention <= 5.10.1 - Unauthenticated Stored Cross-Site Scripting via Webmention Entry Name - **ID:** WPSEC-2026-1121 - **Plugin:** Webmention (`webmention`), https://wordpress.org/plugins/webmention/ - **Affected versions:** from 5.1.2 before 5.10.2 - **Fixed in:** 5.10.2 (Update to 5.10.2 or later.) - **Severity:** High 7.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N) - **Weakness:** CWE-79 - **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-10-16) - **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/webmention - **Fix released:** 2026-10-15 - **Published:** 2026-10-16 - **URL:** https://wpsec.com/vuln/WPSEC-2026-1121/ ## Description The Webmention plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the parsed entry name (for example the source page's og:title, or JSON-LD name/headline) in all versions from 5.1.2 up to, and including, 5.10.1, due to insufficient input sanitization. Unlike the content and summary, the entry name was not sanitized, and it is used as the comment content when the source page has no content or summary, while the plugin disables WordPress's comment content filtering when it stores a Webmention. This makes it possible for unauthenticated attackers who send a Webmention from a page they control to inject arbitrary web scripts in pages that execute whenever a user accesses the page where the Webmention is displayed. ## References - https://wpsec.com/vuln/WPSEC-2026-1121/ - https://plugins.svn.wordpress.org/webmention/tags/5.10.2/ - https://wordpress.org/plugins/webmention/ Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1121/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.