diff --git a/includes/parser/Sanitizer.php b/includes/parser/Sanitizer.php
index 2d6934bb93a..077bae29f85 100644
--- a/includes/parser/Sanitizer.php
+++ b/includes/parser/Sanitizer.php
@@ -512,8 +512,11 @@ class Sanitizer {
 			# * Disallow data attributes used by MediaWiki code
 			# * Ensure that the attribute is not namespaced by banning
 			#   colons.
+			# * Ensure attribute name will be accepted by the HTML
+			#   parser; see
+			#   https://github.com/whatwg/dom/issues/849#issuecomment-1007541209
 			if ( (
-				!preg_match( '/^data-[^:]*$/i', $attribute ) &&
+				!preg_match( '|^data-[^:= \t\r\n/>\0]*$|i', $attribute ) &&
 				!array_key_exists( $attribute, $allowed )
 			) || self::isReservedDataAttribute( $attribute ) ) {
 				continue;