diff --git a/changelog/unreleased/bugfix-iframe-border b/changelog/unreleased/bugfix-iframe-border
new file mode 100644
index 00000000000..d3d35e121fe
--- /dev/null
+++ b/changelog/unreleased/bugfix-iframe-border
@@ -0,0 +1,6 @@
+Bugfix: Remove iFrame border
+
+We fixed a UI issue which showed small borders around iFrames, e.g. in the external app.
+
+https://github.com/owncloud/web/issues/6555
+https://github.com/owncloud/web/pull/6573
diff --git a/packages/web-runtime/src/App.vue b/packages/web-runtime/src/App.vue
index 15f5d5e42b1..155c51dfbd9 100644
--- a/packages/web-runtime/src/App.vue
+++ b/packages/web-runtime/src/App.vue
@@ -202,4 +202,8 @@ body {
   max-height: 100vh;
   overflow-y: hidden;
 }
+
+iframe {
+  border: 0;
+}
 </style>