Index: b/g10/sig-check.c
===================================================================
--- b/g10/sig-check.c
+++ b/g10/sig-check.c
@@ -803,9 +803,14 @@
           kbnode_t ctx = NULL;
           kbnode_t n;
 
-          while ((n = walk_kbnode (kb, &ctx, PKT_PUBLIC_SUBKEY)))
+          while ((n = walk_kbnode (kb, &ctx, 0)))
             {
-              PKT_public_key *subk = n->pkt->pkt.public_key;
+              PKT_public_key *subk;
+
+              if (n->pkt->pkttype != PKT_PUBLIC_SUBKEY)
+                continue;
+
+              subk = n->pkt->pkt.public_key;
               if (sig->keyid[0] == subk->keyid[0]
                   && sig->keyid[1] == subk->keyid[1])
                 /* Issued by a subkey.  */