}
$uid = local_user();
- $url = Strings::escapeTags(trim(defaults($_REQUEST, 'url', '')));
+
+ // Issue 4815: Silently removing a prefixing @
+ $url = ltrim(Strings::escapeTags(trim($_REQUEST['url'] ?? '')), '@!');
// Issue 6874: Allow remote following from Peertube
if (strpos($url, 'acct:') === 0) {