diff --git a/lib/libc/strnlen_secure.c b/lib/libc/strnlen_secure.c
new file mode 100644
index 0000000..36b3571
--- /dev/null
+++ b/lib/libc/strnlen_secure.c
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2024-2025, Altera Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <string.h>
+
+size_t strnlen_secure(const char *str, size_t maxlen)
+{
+	size_t len = 0;
+
+	if (str == NULL) {
+		return 0;
+	}
+
+	while ((len < maxlen) && (str[len] != '\0')) {
+		len++;
+	}
+
+	return len;
+}