diff --git a/app/main.py b/app/main.py
index 90d7701..2c3c101 100644
--- a/app/main.py
+++ b/app/main.py
@@ -39,29 +39,16 @@ app = FastAPI()
 def get_user_identity(request: Request) -> str:
     """Return the logged-in user's identity (Cloudron username).
 
-    Priority: a validated OIDC session cookie (when the oidc addon is active),
-    then the proxyAuth header (legacy fallback during the transition).
+    Reads the validated OIDC session cookie. No header fallback — the app no
+    longer trusts a client-supplied identity header (that path existed only
+    during the proxyAuth → OIDC transition and is now removed).
     """
-    # OIDC session cookie (only when the addon is configured).
-    if oidc.is_oidc_configured():
-        token = request.cookies.get(oidc.SESSION_COOKIE)
-        if token:
-            identity = oidc.read_session(token)
-            if identity:
-                return identity
-
-    # Legacy proxyAuth header fallback.
-    for header in (
-        "x-remote-user",
-        "x-forwarded-user",
-        "x-auth-request-user",
-        "x-auth-request-email",
-        "x-forwarded-email",
-    ):
-        val = request.headers.get(header)
-        if val:
-            return val.strip()
-    return ""
+    if not oidc.is_oidc_configured():
+        return ""
+    token = request.cookies.get(oidc.SESSION_COOKIE)
+    if not token:
+        return ""
+    return oidc.read_session(token) or ""
 
 
 # ---------------------------------------------------------------------------