diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 957786d1b3..0b162f8fab 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -67,6 +67,8 @@ int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 		return ret;
 	write_in_full(STDOUT_FILENO, output.buf, output.len);
 
+	strbuf_release(&input);
+	strbuf_release(&output);
 	free(inpath);
 	return 0;
 }
diff --git a/t/t6200-fmt-merge-msg.sh b/t/t6200-fmt-merge-msg.sh
index 5a221f8ef1..ac57b0e4ae 100755
--- a/t/t6200-fmt-merge-msg.sh
+++ b/t/t6200-fmt-merge-msg.sh
@@ -8,6 +8,7 @@ test_description='fmt-merge-msg test'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-gpg.sh"