diff --git a/src/Composer/Repository/Vcs/GitDriver.php b/src/Composer/Repository/Vcs/GitDriver.php
index 3c3817c7a..0faead2a7 100644
--- a/src/Composer/Repository/Vcs/GitDriver.php
+++ b/src/Composer/Repository/Vcs/GitDriver.php
@@ -37,6 +37,9 @@ class GitDriver extends VcsDriver
     {
         if (Filesystem::isLocalPath($this->url)) {
             $this->url = preg_replace('{[\\/]\.git/?$}', '', $this->url);
+            if (!is_dir($this->url)) {
+                throw new \RuntimeException('Failed to read package information from '.$this->url.' as the path does not exist');
+            }
             $this->repoDir = $this->url;
             $cacheUrl = realpath($this->url);
         } else {
diff --git a/src/Composer/Util/ProcessExecutor.php b/src/Composer/Util/ProcessExecutor.php
index f2f286916..5ec43859a 100644
--- a/src/Composer/Util/ProcessExecutor.php
+++ b/src/Composer/Util/ProcessExecutor.php
@@ -98,11 +98,15 @@ class ProcessExecutor
             $this->io->writeError('Executing command ('.($cwd ?: 'CWD').'): '.$safeCommand);
         }
 
+        // TODO in 2.2, these two checks can be dropped as Symfony 4+ supports them out of the box
         // make sure that null translate to the proper directory in case the dir is a symlink
         // and we call a git command, because msysgit does not handle symlinks properly
         if (null === $cwd && Platform::isWindows() && false !== strpos($command, 'git') && getcwd()) {
             $cwd = realpath(getcwd());
         }
+        if (null !== $cwd && !is_dir($cwd)) {
+            throw new \RuntimeException('The given CWD for the process does not exist: '.$cwd);
+        }
 
         $this->captureOutput = func_num_args() > 3;
         $this->errorOutput = null;
@@ -235,11 +239,15 @@ class ProcessExecutor
             $this->io->writeError('Executing async command ('.($cwd ?: 'CWD').'): '.$safeCommand);
         }
 
+        // TODO in 2.2, these two checks can be dropped as Symfony 4+ supports them out of the box
         // make sure that null translate to the proper directory in case the dir is a symlink
         // and we call a git command, because msysgit does not handle symlinks properly
         if (null === $cwd && Platform::isWindows() && false !== strpos($command, 'git') && getcwd()) {
             $cwd = realpath(getcwd());
         }
+        if (null !== $cwd && !is_dir($cwd)) {
+            throw new \RuntimeException('The given CWD for the process does not exist: '.$cwd);
+        }
 
         // TODO in v3, commands should be passed in as arrays of cmd + args
         if (method_exists('Symfony\Component\Process\Process', 'fromShellCommandline')) {