diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index 69a6d53299..b5e477e7f7 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -2354,10 +2354,6 @@ add_shortcode( 'caption', 'img_caption_shortcode' );
  * @return string HTML content to display the caption.
  */
 function img_caption_shortcode( $attr, $content = '' ) {
-	if ( ! $attr ) {
-		$attr = array();
-	}
-
 	// New-style shortcode with the caption inside the shortcode with the link and image tags.
 	if ( ! isset( $attr['caption'] ) ) {
 		if ( preg_match( '#((?:<a [^>]+>\s*)?<img [^>]+>(?:\s*</a>)?)(.*)#is', $content, $matches ) ) {
diff --git a/src/wp-includes/shortcodes.php b/src/wp-includes/shortcodes.php
index cf88b2195f..bc7ade1a2f 100644
--- a/src/wp-includes/shortcodes.php
+++ b/src/wp-includes/shortcodes.php
@@ -600,11 +600,13 @@ function get_shortcode_atts_regex() {
  * retrieval of the attributes, since all attributes have to be known.
  *
  * @since 2.5.0
+ * @since 6.5.0 The function now always returns an empty array,
+ *              even if the original arguments string cannot be parsed or is empty.
  *
  * @param string $text Shortcode arguments list.
- * @return array|string Array of attribute values keyed by attribute name.
- *                      Returns empty array if there are no attributes.
- *                      Returns the original arguments string if it cannot be parsed.
+ * @return array Array of attribute values keyed by attribute name.
+ *               Returns empty array if there are no attributes
+ *               or if the original arguments string cannot be parsed.
  */
 function shortcode_parse_atts( $text ) {
 	$atts    = array();
@@ -635,8 +637,6 @@ function shortcode_parse_atts( $text ) {
 				}
 			}
 		}
-	} else {
-		$atts = ltrim( $text );
 	}
 
 	return $atts;
diff --git a/tests/phpunit/tests/shortcode.php b/tests/phpunit/tests/shortcode.php
index e8aa82c5a8..2c5b04d02e 100644
--- a/tests/phpunit/tests/shortcode.php
+++ b/tests/phpunit/tests/shortcode.php
@@ -105,9 +105,13 @@ class Tests_Shortcode extends WP_UnitTestCase {
 		return $out;
 	}
 
+	/**
+	 * @ticket 59249
+	 */
 	public function test_noatts() {
 		do_shortcode( '[test-shortcode-tag /]' );
-		$this->assertSame( '', $this->atts );
+		$this->assertIsArray( $this->atts );
+		$this->assertEmpty( $this->atts );
 		$this->assertSame( 'test-shortcode-tag', $this->tagname );
 	}
 
@@ -181,9 +185,13 @@ class Tests_Shortcode extends WP_UnitTestCase {
 		$this->assertSame( 'test-shortcode-tag', $this->tagname );
 	}
 
+	/**
+	 * @ticket 59249
+	 */
 	public function test_noatts_enclosing() {
 		do_shortcode( '[test-shortcode-tag]content[/test-shortcode-tag]' );
-		$this->assertSame( '', $this->atts );
+		$this->assertIsArray( $this->atts );
+		$this->assertEmpty( $this->atts );
 		$this->assertSame( 'content', $this->content );
 		$this->assertSame( 'test-shortcode-tag', $this->tagname );
 	}
@@ -208,10 +216,14 @@ class Tests_Shortcode extends WP_UnitTestCase {
 		$this->assertSame( 'test-shortcode-tag', $this->tagname );
 	}
 
+	/**
+	 * @ticket 59249
+	 */
 	public function test_unclosed() {
 		$out = do_shortcode( '[test-shortcode-tag]' );
 		$this->assertSame( '', $out );
-		$this->assertSame( '', $this->atts );
+		$this->assertIsArray( $this->atts );
+		$this->assertEmpty( $this->atts );
 		$this->assertSame( 'test-shortcode-tag', $this->tagname );
 	}
 
@@ -998,4 +1010,13 @@ EOF;
 		);
 		$this->assertSame( 'test-shortcode-tag', $this->tagname );
 	}
+
+	/**
+	 * @ticket 59249
+	 */
+	public function test_shortcode_parse_atts_empty() {
+		$out = shortcode_parse_atts( '' );
+		$this->assertIsArray( $out, 'Return value is not an array' );
+		$this->assertEmpty( $out, 'Returned array is not empty' );
+	}
 }