diff --git a/builder/remotecontext/git/gitutils.go b/builder/remotecontext/git/gitutils.go
index e042e23971..25c6107bb6 100644
--- a/builder/remotecontext/git/gitutils.go
+++ b/builder/remotecontext/git/gitutils.go
@@ -212,7 +212,7 @@ func (repo gitRepo) gitWithinDir(dir string, args ...string) ([]byte, error) {
 	cmd := exec.Command("git", args...)
 	cmd.Dir = dir
 	// Disable unsafe remote protocols.
-	cmd.Env = append(cmd.Env, "GIT_PROTOCOL_FROM_USER=0")
+	cmd.Env = append(cmd.Environ(), "GIT_PROTOCOL_FROM_USER=0")
 
 	if repo.isolateConfig {
 		cmd.Env = append(cmd.Env,