diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index a5cda2b..31bd899 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -60,11 +60,6 @@ parameters:
 			count: 1
 			path: src/Cookie.php
 
-		-
-			message: "#^Parameter \\#1 \\$string of function rtrim expects string, string\\|null given\\.$#"
-			count: 1
-			path: src/Cookie.php
-
 		-
 			message: "#^Class Http\\\\Message\\\\CookieJar implements generic interface IteratorAggregate but does not specify its types\\: TKey, TValue$#"
 			count: 1
diff --git a/src/Cookie.php b/src/Cookie.php
index ecfbcda..b79fe0a 100644
--- a/src/Cookie.php
+++ b/src/Cookie.php
@@ -511,7 +511,9 @@ private function normalizeDomain($domain)
      */
     private function normalizePath($path)
     {
-        $path = rtrim($path, '/');
+        if (null !== $path) {
+            $path = rtrim($path, '/');
+        }
 
         if (empty($path) or '/' !== substr($path, 0, 1)) {
             $path = '/';