CVE-2026-0686: Webmention <= 5.6.2 - Unauthenticated Blind Server-Side Request Forgery

Severity: high (CVSS 7.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-02 · updated 2026-06-17
Weakness: CWE-918

Description

The Webmention plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 5.6.2 in the 'MF2::parse_authorpage' function via the 'Receiver::post' function. This makes it possible for unauthenticated attackers to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.

Affected products

pfefferle Webmention: through 5.6.2

References

https://github.com/pfefferle/wordpress-webmention/blob/057223cee18a9e93b017d0f21db6ea77a7686489/includes/handler/class-mf2.php#L878
https://plugins.trac.wordpress.org/browser/webmention/tags/5.6.2/includes/class-receiver.php#L260
https://plugins.trac.wordpress.org/browser/webmention/tags/5.6.2/includes/handler/class-mf2.php#L877
https://plugins.trac.wordpress.org/changeset/3494831/webmention
https://www.wordfence.com/threat-intel/vulnerabilities/id/08d15c46-d15f-4803-80be-90bf33335c18?source=cve

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