diff --git a/lib/flow.c b/lib/flow.c
index 393243309..773f2f7b2 100644
--- a/lib/flow.c
+++ b/lib/flow.c
@@ -699,7 +699,7 @@ ipv6_sanity_check(const struct ovs_16aligned_ip6_hdr *nh, size_t size)
         return false;
     }
     /* Jumbo Payload option not supported yet. */
-    if (OVS_UNLIKELY(size - plen > UINT8_MAX)) {
+    if (OVS_UNLIKELY(size - (plen + IPV6_HEADER_LEN) > UINT8_MAX)) {
         return false;
     }