diff --git a/res/composer-schema.json b/res/composer-schema.json
index 2c410b262..6e85af00d 100644
--- a/res/composer-schema.json
+++ b/res/composer-schema.json
@@ -6,7 +6,7 @@
         "name": {
             "type": "string",
             "description": "Package name, including 'vendor-name/' prefix.",
-            "pattern": "^[a-z0-9]([_.-]?[a-z0-9]+)*/[a-z0-9](([_.]?|-{0,2})[a-z0-9]+)*$"
+            "pattern": "^[a-z0-9]([_.-]?[a-z0-9]++)*+/[a-z0-9](([_.]|-{1,2})?[a-z0-9]++)*+$"
         },
         "description": {
             "type": "string",
diff --git a/src/Composer/Package/Loader/ValidatingArrayLoader.php b/src/Composer/Package/Loader/ValidatingArrayLoader.php
index ac7fff385..e5d513c41 100644
--- a/src/Composer/Package/Loader/ValidatingArrayLoader.php
+++ b/src/Composer/Package/Loader/ValidatingArrayLoader.php
@@ -456,7 +456,7 @@ class ValidatingArrayLoader implements LoaderInterface
             return null;
         }
 
-        if (!Preg::isMatch('{^[a-z0-9](?:[_.-]?[a-z0-9]+)*/[a-z0-9](?:(?:[_.]?|-{0,2})[a-z0-9]+)*$}iD', $name)) {
+        if (!Preg::isMatch('{^[a-z0-9](?:[_.-]?[a-z0-9]++)*+/[a-z0-9](?:(?:[_.]|-{1,2})?[a-z0-9]++)*+$}iD', $name)) {
             return $name.' is invalid, it should have a vendor name, a forward slash, and a package name. The vendor and package name can be words separated by -, . or _. The complete name should match "^[a-z0-9]([_.-]?[a-z0-9]+)*/[a-z0-9](([_.]?|-{0,2})[a-z0-9]+)*$".';
         }
 
diff --git a/src/Composer/Util/ProcessExecutor.php b/src/Composer/Util/ProcessExecutor.php
index a4c707cf9..2bcd0b0a4 100644
--- a/src/Composer/Util/ProcessExecutor.php
+++ b/src/Composer/Util/ProcessExecutor.php
@@ -455,7 +455,8 @@ class ProcessExecutor
         // New lines break cmd.exe command parsing
         $argument = strtr($argument, "\n", ' ');
 
-        $quote = strpbrk($argument, " \t") !== false;
+        // In addition to whitespace, commas need quoting to preserve paths
+        $quote = strpbrk($argument, " \t,") !== false;
         $argument = Preg::replace('/(\\\\*)"/', '$1$1\\"', $argument, -1, $dquotes);
         $meta = $dquotes || Preg::isMatch('/%[^%]+%|![^!]+!/', $argument);
 
diff --git a/tests/Composer/Test/Json/ComposerSchemaTest.php b/tests/Composer/Test/Json/ComposerSchemaTest.php
index a458ef1a0..4f836cb9f 100644
--- a/tests/Composer/Test/Json/ComposerSchemaTest.php
+++ b/tests/Composer/Test/Json/ComposerSchemaTest.php
@@ -25,9 +25,9 @@ class ComposerSchemaTest extends TestCase
         $expectedError = array(
             array(
                 'property' => 'name',
-                'message' => 'Does not match the regex pattern ^[a-z0-9]([_.-]?[a-z0-9]+)*/[a-z0-9](([_.]?|-{0,2})[a-z0-9]+)*$',
+                'message' => 'Does not match the regex pattern ^[a-z0-9]([_.-]?[a-z0-9]++)*+/[a-z0-9](([_.]|-{1,2})?[a-z0-9]++)*+$',
                 'constraint' => 'pattern',
-                'pattern' => '^[a-z0-9]([_.-]?[a-z0-9]+)*/[a-z0-9](([_.]?|-{0,2})[a-z0-9]+)*$',
+                'pattern' => '^[a-z0-9]([_.-]?[a-z0-9]++)*+/[a-z0-9](([_.]|-{1,2})?[a-z0-9]++)*+$',
             ),
         );
 
diff --git a/tests/Composer/Test/Util/ProcessExecutorTest.php b/tests/Composer/Test/Util/ProcessExecutorTest.php
index 67769da5b..8af418d4d 100644
--- a/tests/Composer/Test/Util/ProcessExecutorTest.php
+++ b/tests/Composer/Test/Util/ProcessExecutorTest.php
@@ -179,6 +179,9 @@ class ProcessExecutorTest extends TestCase
             // no whitespace must not be quoted
             'no-ws' => array('abc', 'abc', "'abc'"),
 
+            // commas must be quoted
+            'comma' => array('a,bc', '"a,bc"', "'a,bc'"),
+
             // double-quotes must be backslash-escaped
             'dq' => array('a"bc', 'a\^"bc', "'a\"bc'"),