Webmention <= 5.10.1 - Unauthenticated Stored Cross-Site Scripting via Open Graph og:title Meta Tag

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-111109
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-31 07:16:34 UTC
Updated2026-10-31 07:16:34 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 6.1 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Problem Types: CWE-79 | CWE-79 CWE-79 Improper Neutralization of Input During Web Page Generation

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.1CNADECLARED6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Pfefferle Webmention affected 5.10.1 semver Not specified

References

ReferenceSourceLinkTags
plugins.trac.wordpress.org/browser/webmention/tags/5.10.2/includes/class-receiver.php [email protected] plugins.trac.wordpress.org
github.com/pfefferle/wordpress-webmention/pull/698 [email protected] github.com
plugins.trac.wordpress.org/browser/webmention/tags/5.10.1/includes/class-receiver.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/webmention/tags/5.10.1/includes/entity/class-item.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/webmention/tags/5.10.1/includes/entity/class-item.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/webmention/tags/5.10.1/includes/class-receiver.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/webmention/tags/5.10.1/includes/handler/class-meta.php [email protected] plugins.trac.wordpress.org
www.wordfence.com/threat-intel/vulnerabilities/id/0b283d17-b89f-467d-8a79-cdf7b... [email protected] www.wordfence.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: poiri3r (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-10-15T16:14:13.000ZVendor Notified
CNA2026-10-30T18:16:01.000ZDisclosed

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