diff --git a/fast-import.c b/fast-import.c
index c1486cabba..a85275dc68 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1641,6 +1641,8 @@ static int tree_content_get(
 		n = slash1 - p;
 	else
 		n = strlen(p);
+	if (!n)
+		die("Empty path component found in input");
 
 	if (!root->tree)
 		load_tree(root);
@@ -3028,6 +3030,8 @@ static void parse_ls(struct branch *b)
 		store_tree(&leaf);
 
 	print_ls(leaf.versions[1].mode, leaf.versions[1].sha1, p);
+	if (leaf.tree)
+		release_tree_content_recursive(leaf.tree);
 	if (!b || root != &b->branch_tree)
 		release_tree_entry(root);
 }
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 438aaf6b14..0f5b5e5964 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -1306,6 +1306,45 @@ test_expect_success \
 	M 040000 $subdir file3/
 	INPUT_END'
 
+test_expect_success \
+	'N: reject foo/ syntax in copy source' \
+	'test_must_fail git fast-import <<-INPUT_END
+	commit refs/heads/N5C
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	copy with invalid syntax
+	COMMIT
+
+	from refs/heads/branch^0
+	C file2/ file3
+	INPUT_END'
+
+test_expect_success \
+	'N: reject foo/ syntax in rename source' \
+	'test_must_fail git fast-import <<-INPUT_END
+	commit refs/heads/N5D
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	rename with invalid syntax
+	COMMIT
+
+	from refs/heads/branch^0
+	R file2/ file3
+	INPUT_END'
+
+test_expect_success \
+	'N: reject foo/ syntax in ls argument' \
+	'test_must_fail git fast-import <<-INPUT_END
+	commit refs/heads/N5E
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	copy with invalid syntax
+	COMMIT
+
+	from refs/heads/branch^0
+	ls "file2/"
+	INPUT_END'
+
 test_expect_success \
 	'N: copy to root by id and modify' \
 	'echo "hello, world" >expect.foo &&