diff --git a/src/hash_table.c b/src/hash_table.c
index fecdd5c..b07c3ad 100644
--- a/src/hash_table.c
+++ b/src/hash_table.c
@@ -242,7 +242,9 @@
              */
             match->value = malloc(sizeof *match->value * (len + 1));
             LY_CHECK_ERR_RET(!match->value, LOGMEM(ctx), LY_EMEM);
-            memcpy(match->value, value, len);
+            if (len) {
+                memcpy(match->value, value, len);
+            }
             match->value[len] = '\0';
         }
     } else {