diff --git a/clone-pack.c b/clone-pack.c
index c102ca885b..48bee96a88 100644
--- a/clone-pack.c
+++ b/clone-pack.c
@@ -34,6 +34,12 @@ static void write_one_ref(struct ref *ref)
 	int fd;
 	char *hex;
 
+	if (!strncmp(ref->name, "refs/", 5) &&
+	    check_ref_format(ref->name + 5)) {
+		error("refusing to create funny ref '%s' locally", ref->name);
+		return;
+	}
+
 	if (safe_create_leading_directories(path))
 		die("unable to create leading directory for %s", ref->name);
 	fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
diff --git a/git-parse-remote.sh b/git-parse-remote.sh
index 4d8a572a99..32f10855b6 100755
--- a/git-parse-remote.sh
+++ b/git-parse-remote.sh
@@ -94,6 +94,12 @@ canon_refs_list_for_fetch () {
 		heads/* | tags/* ) local="refs/$local" ;;
 		*) local="refs/heads/$local" ;;
 		esac
+
+		if local_ref_name=$(expr "$local" : 'refs/\(.*\)')
+		then
+		   git-check-ref-format "$local_ref_name" ||
+		   die "* refusing to create funny ref '$local_ref_name' locally"
+		fi
 		echo "${dot_prefix}${force}${remote}:${local}"
 		dot_prefix=.
 	done
diff --git a/receive-pack.c b/receive-pack.c
index 06857eb77f..8f157bc3f0 100644
--- a/receive-pack.c
+++ b/receive-pack.c
@@ -95,6 +95,10 @@ static int update(const char *name,
 	char new_hex[60], *old_hex, *lock_name;
 	int newfd, namelen, written;
 
+	if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5))
+		return error("refusing to create funny ref '%s' locally",
+			     name);
+
 	namelen = strlen(name);
 	lock_name = xmalloc(namelen + 10);
 	memcpy(lock_name, name, namelen);