diff --git a/apps/login/src/lib/zitadel.ts b/apps/login/src/lib/zitadel.ts
index 549bf65577..f1ccb385d5 100644
--- a/apps/login/src/lib/zitadel.ts
+++ b/apps/login/src/lib/zitadel.ts
@@ -1515,7 +1515,11 @@ export function createServerTransport(
                 .CUSTOM_REQUEST_HEADERS!.split(",")
                 .forEach((header) => {
                   const kv = header.split(":");
-                  req.header.set(kv[0], kv[1]);
+                  if (kv.length === 2) {
+                    req.header.set(kv[0].trim(), kv[1].trim());
+                  } else {
+                    console.warn(`Skipping malformed header: ${header}`);
+                  }
                 });
               return next(req);
             };