diff --git a/ext/standard/pack.c b/ext/standard/pack.c
index 209ddf8de0c..f088890a59a 100644
--- a/ext/standard/pack.c
+++ b/ext/standard/pack.c
@@ -692,7 +692,9 @@ PHP_FUNCTION(unpack)
 							len = size * 2;
 						} 
 
-						len -= argb % 2;
+						if (argb > 0) {	
+							len -= argb % 2;
+						}
 
 						buf = emalloc(len + 1);
 
diff --git a/ext/standard/tests/strings/bug36148.phpt b/ext/standard/tests/strings/bug36148.phpt
new file mode 100644
index 00000000000..06caac33345
--- /dev/null
+++ b/ext/standard/tests/strings/bug36148.phpt
@@ -0,0 +1,29 @@
+--TEST--
+Bug #36148 (unpack("H*hex", $data) is adding an extra character to the end of the string)
+--FILE--
+<?php
+$values = array("a", "aa", "aaa", "aaaa");
+foreach ($values as $value) {
+	$a = pack("H*", $value);
+	$b = unpack("H*", $a);
+	echo $value.": ";
+	var_dump($b);
+}
+?>
+--EXPECT--
+a: array(1) {
+  [1]=>
+  string(2) "a0"
+}
+aa: array(1) {
+  [1]=>
+  string(2) "aa"
+}
+aaa: array(1) {
+  [1]=>
+  string(4) "aaa0"
+}
+aaaa: array(1) {
+  [1]=>
+  string(4) "aaaa"
+}