CVE-2026-111109 json
Webmention <= 5.10.1 - Unauthenticated Stored Cross-Site Scripting via Open Graph og:title Meta Tag
published 9d ago modified 7d ago also EUVD-2026-114592
- cvss
- 6.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 20%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- github.com/pfefferle/wordpress-webmention#698 pull request
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 8d ago
Exploit prediction
0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected products
- pfefferle Webmention
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- github.com /pfefferle/wordpress-webmention/pull/698
- wordfence.com /threat-intel/vulnerabilities/id/0b283d17-b89f-467d-8a79-cdf7b9bfdb65?source=cve
- plugins.trac.wordpress.org /browser/webmention/tags/5.10.1/includes/handler/class-meta.php#L78
- plugins.trac.wordpress.org /browser/webmention/tags/5.10.1/includes/entity/class-item.php#L297
- plugins.trac.wordpress.org /browser/webmention/tags/5.10.1/includes/class-receiver.php#L453
- plugins.trac.wordpress.org /browser/webmention/tags/5.10.1/includes/entity/class-item.php#L125
- plugins.trac.wordpress.org /browser/webmention/tags/5.10.1/includes/class-receiver.php#L267
- plugins.trac.wordpress.org /browser/webmention/tags/5.10.2/includes/class-receiver.php
Sources
- CVE List CVE-2026-111109
- NVD CVE-2026-111109
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