Fediverse Embeds embeds fediverse posts on WordPress sites. Prior to version 1.5.8, Fediverse Embeds registered an unauthenticated REST route ftf/media-proxy (includes/Media_Proxy.php) with permission_callback => __return_true that accepted a base64-encoded URL and forwarded it to wp_remote_get($url) without enforcing any allowlist. The plugin's source contained a comment block explicitly acknowledging that the request should be validated against allowed fediverse domains, but in 1.5.7 the validation only set a local $can_download_media flag that was never read. The full response body was echoed back to the caller, so this was a full-read SSRF / open proxy reachable by any anonymous visitor. This issue has been patched in version 1.5.8.
Fediverse Embeds embeds fediverse posts on WordPress sites. Prior to version 1.5.9, Fediverse Embeds registered the unauthenticated AJAX action wp_ajax_nopriv_ftf_get_site_info (includes/Site_Info.php) that verified a nonce ftf-fediverse-embeds-nonce and then called file_get_html($site_url) on the attacker-supplied URL. The same nonce was enqueued onto every public page containing a fediverse embed (via includes/Enqueue_Assets.php lines 41-46 + includes/Helpers.php lines 64-83), so the nonce gate was not an authentication boundary; any visitor of a public post with an embed could grab it and reuse it. This issue has been patched in version 1.5.9.