diff --git src/wp-includes/formatting.php src/wp-includes/formatting.php
index 4fb4135..47f8e5f 100644
--- src/wp-includes/formatting.php
+++ src/wp-includes/formatting.php
@@ -3168,7 +3168,7 @@ function wp_targeted_link_rel_callback( $matches ) {
preg_match( $attr_regex, $link_html, $rel_match );
}
- if ( ! empty( $rel_match[0] ) ) {
+ if ( ! empty( $rel_match[0] ) && preg_match( '#(^\s*|\s+)rel\s*=#', $link_html ) ) {
$parts = preg_split( '|\s+|', strtolower( $rel_match[2] ) );
$parts = array_map( 'esc_attr', $parts );
$needed = explode( ' ', $rel );
diff --git tests/phpunit/tests/formatting/WPTargetedLinkRel.php tests/phpunit/tests/formatting/WPTargetedLinkRel.php
index 8be254a..9a12df8 100644
--- tests/phpunit/tests/formatting/WPTargetedLinkRel.php
+++ tests/phpunit/tests/formatting/WPTargetedLinkRel.php
@@ -139,4 +139,37 @@ class Tests_Targeted_Link_Rel extends WP_UnitTestCase {
$this->assertEquals( $expected, wp_targeted_link_rel( $content ) );
}
+ /**
+ * Ensure rel parameter in href is ignored when no rel attribute.
+ *
+ * @ticket 48261
+ */
+ public function test_ignore_rel_param_in_href_when_no_rel_attribute() {
+ $content = 'Anchor Text';
+ $expected = 'Anchor Text';
+ $this->assertEquals( $expected, wp_targeted_link_rel( $content ) );
+ }
+
+ /**
+ * Ensure rel parameter in href is ignored when rel attribute exists.
+ *
+ * @ticket 48261
+ */
+ public function test_ignore_rel_param_in_href_when_rel_attribute() {
+ $content = 'Anchor Text';
+ $expected = 'Anchor Text';
+ $this->assertEquals( $expected, wp_targeted_link_rel( $content ) );
+ }
+
+ /**
+ * Ensure rel parameter in href is ignored when rel is the first attribute.
+ *
+ * @ticket 48261
+ */
+ public function test_ignore_rel_param_in_href_when_rel_first_attribute() {
+ $content = 'Anchor Text';
+ $expected = 'Anchor Text';
+ $this->assertEquals( $expected, wp_targeted_link_rel( $content ) );
+ }
+
}