diff --git a/src/editors/sharedComponents/TinyMceWidget/hooks.ts b/src/editors/sharedComponents/TinyMceWidget/hooks.ts
index f89f1320ad..4355855f99 100644
--- a/src/editors/sharedComponents/TinyMceWidget/hooks.ts
+++ b/src/editors/sharedComponents/TinyMceWidget/hooks.ts
@@ -457,6 +457,9 @@ export const editorConfig = ({
valid_elements: '*[*]',
// FIXME: this is passing 'utf-8', which is not a valid entity_encoding value. It should be 'named' etc.
entity_encoding: 'utf-8' as any,
+ // Protect self-closing tags from being mangled,
+ // to preserve backwards compatibility with content that relied on this behavior
+ protect: [/