Clobber any existing sudo leases before execution to prevent malicious code gaining root privileges.

src/Composer/Console/Application.php

@@ -133,13 +133,17 @@ class Application extends BaseApplication
                 $input->setInteractive(false);
             }
 
-            if (!Platform::isWindows() && function_exists('posix_getuid') && posix_getuid() === 0) {
-                $io->writeError('<warning>Running composer as root is highly discouraged as packages, plugins and scripts cannot always be trusted</warning>');
-                if ($uid = getenv('SUDO_UID')) {
-                    // Silently clobber any sudo credentials on the invoking user to avoid privilege escalations later on
-                    // ref. https://github.com/composer/composer/issues/5119
-                    exec("sudo -u \\#{$uid} sudo -K > /dev/null 2>&1");
+            if (!Platform::isWindows()) {
+                if (function_exists('posix_getuid') && posix_getuid() === 0) {
+                    $io->writeError('<warning>Running composer as root is highly discouraged as packages, plugins and scripts cannot always be trusted</warning>');
+                    if ($uid = getenv('SUDO_UID')) {
+                        // Silently clobber any sudo credentials on the invoking user to avoid privilege escalations later on
+                        // ref. https://github.com/composer/composer/issues/5119
+                        exec("sudo -u \\#{$uid} sudo -K > /dev/null 2>&1");
+                    }
                 }
+                // Silently clobber any remaining sudo leases on the current user as well to avoid privilege escalations
+                exec("sudo -K > /dev/null 2>&1");
             }
 
             // switch working dir