diff --git a/crates/app/src/routes/api/v1/auth/profile.rs b/crates/app/src/routes/api/v1/auth/profile.rs
index aec31ef..c5bbcc1 100644
--- a/crates/app/src/routes/api/v1/auth/profile.rs
+++ b/crates/app/src/routes/api/v1/auth/profile.rs
@@ -144,6 +144,14 @@ pub async fn update_user_settings_request(
         return Json(Error::DataTooLong("warning".to_string()).into());
     }
 
+    if req.mail_signature.len() > 2048 {
+        return Json(Error::DataTooLong("mail signature".to_string()).into());
+    }
+
+    if req.forum_signature.len() > 2048 {
+        return Json(Error::DataTooLong("forum signature".to_string()).into());
+    }
+
     // check percentage themes
     if !req.theme_sat.is_empty() && !req.theme_sat.ends_with("%") {
         req.theme_sat = format!("{}%", req.theme_sat)