diff --git a/package-lock.json b/package-lock.json
index bdc02efc66..0373109ee3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4083,6 +4083,26 @@
 					"integrity": "sha512-+JHkqs9LC/JPp51yy1hzs3lQ7qeuWCwOcSzpQNeeY/G7oSpnF61vxt7hRh87zNRTr6ob2ndy0W8rVzhgrcA+Gw==",
 					"dev": true
 				},
+				"puppeteer": {
+					"version": "npm:puppeteer-core@5.5.0",
+					"resolved": "https://registry.npmjs.org/puppeteer-core/-/puppeteer-core-5.5.0.tgz",
+					"integrity": "sha512-tlA+1n+ziW/Db03hVV+bAecDKse8ihFRXYiEypBe9IlLRvOCzYFG6qrCMBYK34HO/Q/Ecjc+tvkHRAfLVH+NgQ==",
+					"dev": true,
+					"requires": {
+						"debug": "^4.1.0",
+						"devtools-protocol": "0.0.818844",
+						"extract-zip": "^2.0.0",
+						"https-proxy-agent": "^4.0.0",
+						"node-fetch": "^2.6.1",
+						"pkg-dir": "^4.2.0",
+						"progress": "^2.0.1",
+						"proxy-from-env": "^1.0.0",
+						"rimraf": "^3.0.2",
+						"tar-fs": "^2.0.0",
+						"unbzip2-stream": "^1.3.3",
+						"ws": "^7.2.3"
+					}
+				},
 				"rimraf": {
 					"version": "3.0.2",
 					"resolved": "https://registry.npmjs.org/rimraf/-/rimraf-3.0.2.tgz",
@@ -5890,7 +5910,7 @@
 		},
 		"browserify-aes": {
 			"version": "1.2.0",
-			"resolved": "http://registry.npmjs.org/browserify-aes/-/browserify-aes-1.2.0.tgz",
+			"resolved": "https://registry.npmjs.org/browserify-aes/-/browserify-aes-1.2.0.tgz",
 			"integrity": "sha512-+7CHXqGuspUn/Sl5aO7Ea0xWGAtETPXNSAjHo48JfLdPWcMng33Xe4znFvQweqc/uzk5zSOI3H52CYnjCfb5hA==",
 			"dev": true,
 			"requires": {
@@ -18804,80 +18824,6 @@
 			"resolved": "https://registry.npmjs.org/punycode/-/punycode-2.1.1.tgz",
 			"integrity": "sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A=="
 		},
-		"puppeteer": {
-			"version": "npm:puppeteer-core@5.5.0",
-			"resolved": "https://registry.npmjs.org/puppeteer-core/-/puppeteer-core-5.5.0.tgz",
-			"integrity": "sha512-tlA+1n+ziW/Db03hVV+bAecDKse8ihFRXYiEypBe9IlLRvOCzYFG6qrCMBYK34HO/Q/Ecjc+tvkHRAfLVH+NgQ==",
-			"dev": true,
-			"requires": {
-				"debug": "^4.1.0",
-				"devtools-protocol": "0.0.818844",
-				"extract-zip": "^2.0.0",
-				"https-proxy-agent": "^4.0.0",
-				"node-fetch": "^2.6.1",
-				"pkg-dir": "^4.2.0",
-				"progress": "^2.0.1",
-				"proxy-from-env": "^1.0.0",
-				"rimraf": "^3.0.2",
-				"tar-fs": "^2.0.0",
-				"unbzip2-stream": "^1.3.3",
-				"ws": "^7.2.3"
-			},
-			"dependencies": {
-				"find-up": {
-					"version": "4.1.0",
-					"resolved": "https://registry.npmjs.org/find-up/-/find-up-4.1.0.tgz",
-					"integrity": "sha512-PpOwAdQ/YlXQ2vj8a3h8IipDuYRi3wceVQQGYWxNINccq40Anw7BlsEXCMbt1Zt+OLA6Fq9suIpIWD0OsnISlw==",
-					"dev": true,
-					"requires": {
-						"locate-path": "^5.0.0",
-						"path-exists": "^4.0.0"
-					}
-				},
-				"locate-path": {
-					"version": "5.0.0",
-					"resolved": "https://registry.npmjs.org/locate-path/-/locate-path-5.0.0.tgz",
-					"integrity": "sha512-t7hw9pI+WvuwNJXwk5zVHpyhIqzg2qTlklJOf0mVxGSbe3Fp2VieZcduNYjaLDoy6p9uGpQEGWG87WpMKlNq8g==",
-					"dev": true,
-					"requires": {
-						"p-locate": "^4.1.0"
-					}
-				},
-				"p-locate": {
-					"version": "4.1.0",
-					"resolved": "https://registry.npmjs.org/p-locate/-/p-locate-4.1.0.tgz",
-					"integrity": "sha512-R79ZZ/0wAxKGu3oYMlz8jy/kbhsNrS7SKZ7PxEHBgJ5+F2mtFW2fK2cOtBh1cHYkQsbzFV7I+EoRKe6Yt0oK7A==",
-					"dev": true,
-					"requires": {
-						"p-limit": "^2.2.0"
-					}
-				},
-				"path-exists": {
-					"version": "4.0.0",
-					"resolved": "https://registry.npmjs.org/path-exists/-/path-exists-4.0.0.tgz",
-					"integrity": "sha512-ak9Qy5Q7jYb2Wwcey5Fpvg2KoAc/ZIhLSLOSBmRmygPsGwkVVt0fZa0qrtMz+m6tJTAHfZQ8FnmB4MG4LWy7/w==",
-					"dev": true
-				},
-				"pkg-dir": {
-					"version": "4.2.0",
-					"resolved": "https://registry.npmjs.org/pkg-dir/-/pkg-dir-4.2.0.tgz",
-					"integrity": "sha512-HRDzbaKjC+AOWVXxAU/x54COGeIv9eb+6CkDSQoNTt4XyWoIJvuPsXizxu/Fr23EiekbtZwmh1IcIG/l/a10GQ==",
-					"dev": true,
-					"requires": {
-						"find-up": "^4.0.0"
-					}
-				},
-				"rimraf": {
-					"version": "3.0.2",
-					"resolved": "https://registry.npmjs.org/rimraf/-/rimraf-3.0.2.tgz",
-					"integrity": "sha512-JZkJMZkAGFFPP2YqXZXPbMlMBgsxzE8ILs4lMIX/2o0L9UBw9O/Y3o6wFw/i9YLapcUJWwqbi3kdxIPdC62TIA==",
-					"dev": true,
-					"requires": {
-						"glob": "^7.1.3"
-					}
-				}
-			}
-		},
 		"q": {
 			"version": "1.5.1",
 			"resolved": "https://registry.npmjs.org/q/-/q-1.5.1.tgz",
diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index 89b972603b..f5b6a39968 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -1869,6 +1869,11 @@ function wp_filter_content_tags( $content, $context = null ) {
  * @return string Converted `img` tag with `loading` attribute added.
  */
 function wp_img_tag_add_loading_attr( $image, $context ) {
+	// Images should have source and dimension attributes for the `loading` attribute to be added.
+	if ( false === strpos( $image, ' src="' ) || false === strpos( $image, ' width="' ) || false === strpos( $image, ' height="' ) ) {
+		return $image;
+	}
+
 	/**
 	 * Filters the `loading` attribute value to add to an image. Default `lazy`.
 	 *
@@ -1889,11 +1894,6 @@ function wp_img_tag_add_loading_attr( $image, $context ) {
 			$value = 'lazy';
 		}
 
-		// Images should have source and dimension attributes for the `loading` attribute to be added.
-		if ( false === strpos( $image, ' src="' ) || false === strpos( $image, ' width="' ) || false === strpos( $image, ' height="' ) ) {
-			return $image;
-		}
-
 		return str_replace( '<img', '<img loading="' . esc_attr( $value ) . '"', $image );
 	}
 
@@ -1989,6 +1989,17 @@ function wp_img_tag_add_srcset_and_sizes_attr( $image, $context, $attachment_id
  * @return string Converted `iframe` tag with `loading` attribute added.
  */
 function wp_iframe_tag_add_loading_attr( $iframe, $context ) {
+	// Iframes with fallback content (see `wp_filter_oembed_result()`) should not be lazy-loaded because they are
+	// visually hidden initially.
+	if ( false !== strpos( $iframe, ' data-secret="' ) ) {
+		return $iframe;
+	}
+
+	// Iframes should have source and dimension attributes for the `loading` attribute to be added.
+	if ( false === strpos( $iframe, ' src="' ) || false === strpos( $iframe, ' width="' ) || false === strpos( $iframe, ' height="' ) ) {
+		return $iframe;
+	}
+
 	/**
 	 * Filters the `loading` attribute value to add to an iframe. Default `lazy`.
 	 *
@@ -2009,11 +2020,6 @@ function wp_iframe_tag_add_loading_attr( $iframe, $context ) {
 			$value = 'lazy';
 		}
 
-		// Iframes should have source and dimension attributes for the `loading` attribute to be added.
-		if ( false === strpos( $iframe, ' src="' ) || false === strpos( $iframe, ' width="' ) || false === strpos( $iframe, ' height="' ) ) {
-			return $iframe;
-		}
-
 		return str_replace( '<iframe', '<iframe loading="' . esc_attr( $value ) . '"', $iframe );
 	}
 
diff --git a/tests/phpunit/tests/media.php b/tests/phpunit/tests/media.php
index bc9b593d15..9a28743f5e 100644
--- a/tests/phpunit/tests/media.php
+++ b/tests/phpunit/tests/media.php
@@ -2941,6 +2941,19 @@ EOF;
 	function test_wp_iframe_tag_add_loading_attr_opt_out() {
 		$iframe = '<iframe src="https://www.example.com" width="640" height="360"></iframe>';
 		add_filter( 'wp_iframe_tag_add_loading_attr', '__return_false' );
+		$iframe = wp_iframe_tag_add_loading_attr( $iframe, 'test' );
+
+		$this->assertNotContains( ' loading=', $iframe );
+	}
+
+	/**
+	 * @ticket 52768
+	 */
+	function test_wp_iframe_tag_add_loading_attr_skip_wp_embed() {
+		$iframe   = '<iframe src="https://www.example.com" width="640" height="360"></iframe>';
+		$fallback = '<blockquote>Fallback content.</blockquote>';
+		$iframe   = wp_filter_oembed_result( $fallback . $iframe, (object) array( 'type' => 'rich' ), 'https://www.example.com' );
+		$iframe   = wp_iframe_tag_add_loading_attr( $iframe, 'test' );
 
 		$this->assertNotContains( ' loading=', $iframe );
 	}