diff --git a/system/Validation/FormatRules.php b/system/Validation/FormatRules.php
index e54c78a3c008..e0e527215bf9 100644
--- a/system/Validation/FormatRules.php
+++ b/system/Validation/FormatRules.php
@@ -294,7 +294,13 @@ public function valid_emails(string $str = null): bool
 
 		foreach (explode(',', $str) as $email)
 		{
-			if (trim($email) !== '' && $this->valid_email(trim($email)) === false)
+			$email = trim($email);
+			if ($email === '')
+			{
+				return false;
+			}
+
+			if ($this->valid_email($email) === false)
 			{
 				return false;
 			}
diff --git a/tests/system/Validation/FormatRulesTest.php b/tests/system/Validation/FormatRulesTest.php
index bd5c4c9dc149..4cba651aa8c0 100644
--- a/tests/system/Validation/FormatRulesTest.php
+++ b/tests/system/Validation/FormatRulesTest.php
@@ -241,6 +241,10 @@ public function emailsProvider()
 				null,
 				false,
 			],
+			[
+				',',
+				false,
+			],
 		];
 	}