CVE-2026-12516 is a Server-Side Request Forgery vulnerability in the Fediverse Embeds WordPress plugin prior to version 1.5.8. The vulnerability arises because the plugin does not validate the destination of server-side requests made through an unauthenticated media-proxying endpoint. As a result, attackers can cause the server to fetch arbitrary URLs, including those on internal or private networks, and retrieve the response body. This leads to an open proxy condition and full-read SSRF, potentially exposing sensitive internal resources.

An attacker can leverage this vulnerability to make the affected server perform arbitrary HTTP requests to internal or external systems and read the responses. This can lead to unauthorized disclosure of sensitive information from internal services or networks that are otherwise inaccessible externally. The open proxy behavior may also be abused for further attacks or anonymizing malicious traffic.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch is currently documented, users should monitor the vendor's announcements for updates. Until a patch is available, consider disabling or restricting access to the media-proxying endpoint if possible to mitigate exploitation risk.