diff --git a/src/Composer/Repository/Vcs/GitDriver.php b/src/Composer/Repository/Vcs/GitDriver.php
index 143144712..e2a3a9eb0 100644
--- a/src/Composer/Repository/Vcs/GitDriver.php
+++ b/src/Composer/Repository/Vcs/GitDriver.php
@@ -80,7 +80,7 @@ class GitDriver extends VcsDriver
         $this->getTags();
         $this->getBranches();
 
-        $this->cache = new Cache($this->io, $this->config->get('cache-repo-dir').'/'.$this->url);
+        $this->cache = new Cache($this->io, $this->config->get('cache-repo-dir').'/'.preg_replace('{[^a-z0-9.]}i', '-', $this->url));
     }
 
     /**