diff --git a/src/lint/linter/ArcanistPEP8Linter.php b/src/lint/linter/ArcanistPEP8Linter.php
--- a/src/lint/linter/ArcanistPEP8Linter.php
+++ b/src/lint/linter/ArcanistPEP8Linter.php
@@ -59,7 +59,7 @@
     list($stdout) = execx('%C --version', $this->getExecutableCommand());
 
     $matches = array();
-    if (preg_match('/^(?P<version>\d+\.\d+\.\d+)$/', $stdout, $matches)) {
+    if (preg_match('/^(?P<version>\d+\.\d+(?:\.\d+)?)\b/', $stdout, $matches)) {
       return $matches['version'];
     } else {
       return false;