diff --git a/apps/web/src/components/structures/RoomView.tsx b/apps/web/src/components/structures/RoomView.tsx
index 26b5e673e5..5a28be3da7 100644
--- a/apps/web/src/components/structures/RoomView.tsx
+++ b/apps/web/src/components/structures/RoomView.tsx
@@ -498,6 +498,8 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
             showJoinLeaves: true,
             showAvatarChanges: true,
             showDisplaynameChanges: true,
+            // Default to false to avoid any accidental leakage.
+            showUrlPreview: false,
             matrixClientIsReady: context.client?.isInitialSyncComplete(),
             mainSplitContentType: MainSplitContentType.Timeline,
             timelineRenderingType: TimelineRenderingType.Room,
diff --git a/apps/web/test/test-utils/room.ts b/apps/web/test/test-utils/room.ts
index ecce6818b0..8c05e02c05 100644
--- a/apps/web/test/test-utils/room.ts
+++ b/apps/web/test/test-utils/room.ts
@@ -75,6 +75,7 @@ export function getRoomContext(room: Room, override: Partial<RoomContextType>):
         showJoinLeaves: true,
         showAvatarChanges: true,
         showDisplaynameChanges: true,
+        showUrlPreview: false,
         matrixClientIsReady: false,
         timelineRenderingType: TimelineRenderingType.Room,
         mainSplitContentType: MainSplitContentType.Timeline,
diff --git a/apps/web/test/unit-tests/components/views/rooms/SendMessageComposer-test.tsx b/apps/web/test/unit-tests/components/views/rooms/SendMessageComposer-test.tsx
index fcc215a73f..c6e5109406 100644
--- a/apps/web/test/unit-tests/components/views/rooms/SendMessageComposer-test.tsx
+++ b/apps/web/test/unit-tests/components/views/rooms/SendMessageComposer-test.tsx
@@ -67,6 +67,7 @@ describe("<SendMessageComposer/>", () => {
         showJoinLeaves: true,
         showAvatarChanges: true,
         showDisplaynameChanges: true,
+        showUrlPreview: false,
         matrixClientIsReady: false,
         timelineRenderingType: TimelineRenderingType.Room,
         mainSplitContentType: MainSplitContentType.Timeline,