diff --git a/src/Filesystem/Mime.php b/src/Filesystem/Mime.php
index c7344a485a..2f48331c18 100644
--- a/src/Filesystem/Mime.php
+++ b/src/Filesystem/Mime.php
@@ -270,36 +270,35 @@ public static function toExtension(string|null $mime = null): string|false
 	/**
 	 * Returns all available extensions for a given MIME type
 	 */
-	public static function toExtensions(string|null $mime = null, bool $matchWildcards = false): array
-	{
-		$extensions = [];
-		$testMime = fn (string $v) => static::matches($v, $mime);
+	public static function toExtensions(
+		string|null $mime = null,
+		bool $matchWildcards = false
+	): array {
+		// get all extensions
+		$extensions = array_keys(static::$types);
+
+		// filter extensions for given MIME type
+		$extensions = A::filter(
+			$extensions,
+			function ($extension) use ($mime, $matchWildcards) {
+				// get corresponding MIME types as array
+				$mimes = A::wrap(static::$types[$extension]);
 
-		foreach (static::$types as $key => $value) {
-			if (is_array($value) === true) {
 				if ($matchWildcards === true) {
-					if (A::some($value, $testMime)) {
-						$extensions[] = $key;
-					}
-				} else {
-					if (in_array($mime, $value) === true) {
-						$extensions[] = $key;
-					}
-				}
-			} else {
-				if ($matchWildcards === true) {
-					if ($testMime($value) === true) {
-						$extensions[] = $key;
-					}
-				} else {
-					if ($value === $mime) {
-						$extensions[] = $key;
-					}
+					// check if at least one MIME type with wildcards matches
+					return A::some(
+						$mimes,
+						fn (string $v): bool => static::matches($v, $mime)
+					);
 				}
+
+				// check if at least one MIME type matches exactly
+				return in_array($mime, $mimes);
 			}
-		}
+		);
 
-		return $extensions;
+		// renumber array with consecutive keys
+		return array_values($extensions);
 	}
 
 	/**
diff --git a/tests/Filesystem/MimeTest.php b/tests/Filesystem/MimeTest.php
index b0025cb956..35b274a942 100644
--- a/tests/Filesystem/MimeTest.php
+++ b/tests/Filesystem/MimeTest.php
@@ -130,21 +130,31 @@ public function testToExtensions()
 
 		$extensions = Mime::toExtensions('text/css');
 		$this->assertSame(['css'], $extensions);
+	}
 
-		// test matchWildcards: false (default value)
+	/**
+	 * @covers ::toExtensions
+	 */
+	public function testToExtensionsMatchWildcards()
+	{
+		// matchWildcards: false (default value)
 		$extensions = Mime::toExtensions('image/*');
 		$this->assertCount(0, $extensions);
 
-		// test matchWildcards: true
+		// matchWildcards: true
 		$extensions = Mime::toExtensions('image/*', true);
-		// use we only check for a positive and negative subset instead of a complete list,
-		// this should make sure the test doesn't break when a new image type is added
-		$shouldContain = ['jpg', 'jpeg', 'gif', 'png'];
-		$shouldNotContain = ['js', 'pdf', 'zip', 'docx'];
-		foreach ($shouldContain as $ext) {
+
+		// we only check for a positive and negative subset
+		// instead of a complete list to make sure the test
+		// doesn't break when a new image type is added
+
+		// should contain
+		foreach (['jpg', 'jpeg', 'gif', 'png'] as $ext) {
 			$this->assertContains($ext, $extensions);
 		}
-		foreach ($shouldNotContain as $ext) {
+
+		// should not contain
+		foreach (['js', 'pdf', 'zip', 'docx'] as $ext) {
 			$this->assertNotContains($ext, $extensions);
 		}
 	}