diff --git a/library/asn1write.c b/library/asn1write.c
index 775a9ef530fb469a01c50f06059794fdebc8b58b..415357b7b5923a1feaddd213cc2dd9f3214a5d11 100644
--- a/library/asn1write.c
+++ b/library/asn1write.c
@@ -412,6 +412,7 @@ mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
     } else if (val_len == 0) {
         mbedtls_free(cur->val.p);
         cur->val.p = NULL;
+        cur->val.len = 0;
     } else if (cur->val.len != val_len) {
         /*
          * Enlarge existing value buffer if needed