diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index 93b4df2df4505..1382f2c10c07c 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -3247,6 +3247,7 @@ function wp_check_filetype_and_ext( $file, $filename, $mimes = null ) {
 					'text/richtext',
 					'text/tsv',
 					'text/vtt',
+					'application/json',
 				),
 				true
 			)
diff --git a/tests/phpunit/data/uploads/test.json b/tests/phpunit/data/uploads/test.json
new file mode 100644
index 0000000000000..7deb8b173227b
--- /dev/null
+++ b/tests/phpunit/data/uploads/test.json
@@ -0,0 +1 @@
+"just a string"
diff --git a/tests/phpunit/tests/functions.php b/tests/phpunit/tests/functions.php
index b6080da780ba8..ba26d7f99e268 100644
--- a/tests/phpunit/tests/functions.php
+++ b/tests/phpunit/tests/functions.php
@@ -1839,6 +1839,32 @@ public function data_wp_check_filetype_and_ext() {
 		return $data;
 	}
 
+	/**
+	 * @ticket 54193
+	 * @group ms-excluded
+	 * @requires extension fileinfo
+	 */
+	public function test_wp_check_filetype_and_ext_with_filtered_json() {
+		$file     = DIR_TESTDATA . '/uploads/test.json';
+		$filename = 'test.json';
+
+		$expected = array(
+			'ext'             => 'json',
+			'type'            => 'application/json',
+			'proper_filename' => false,
+		);
+
+		add_filter(
+			'upload_mimes',
+			static function ( $mimes ) {
+				$mimes['json'] = 'application/json';
+				return $mimes;
+			}
+		);
+
+		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
+	}
+
 	/**
 	 * @ticket 39550
 	 * @group ms-excluded