src/crypto/x509/verify.go      |  2 +-
 src/crypto/x509/verify_test.go | 19 +++++++++++++++++++

diff --git a/src/crypto/x509/verify.go b/src/crypto/x509/verify.go
index 345d434453c44b98b00be4899862c57d1c8973a1..56a1a1725cc3314b107f97885b2f8c421c9d4b88 100644
--- a/src/crypto/x509/verify.go
+++ b/src/crypto/x509/verify.go
@@ -899,7 +899,7 @@ 		hintCert *Certificate
 	)
 
 	considerCandidate := func(certType int, candidate *Certificate) {
-		if alreadyInChain(candidate, currentChain) {
+		if candidate.PublicKey == nil || alreadyInChain(candidate, currentChain) {
 			return
 		}
 
diff --git a/src/crypto/x509/verify_test.go b/src/crypto/x509/verify_test.go
index 37f13f861f1b541fc10c98fe7a584618d33b2dcc..6d09d24da2389b9b47a064139f97da5e0d0f3826 100644
--- a/src/crypto/x509/verify_test.go
+++ b/src/crypto/x509/verify_test.go
@@ -2718,3 +2718,22 @@ 		})
 	}
 
 }
+
+func TestVerifyNilPubKey(t *testing.T) {
+	c := &Certificate{
+		RawIssuer:      []byte{1, 2, 3},
+		AuthorityKeyId: []byte{1, 2, 3},
+	}
+	opts := &VerifyOptions{}
+	opts.Roots = NewCertPool()
+	r := &Certificate{
+		RawSubject:   []byte{1, 2, 3},
+		SubjectKeyId: []byte{1, 2, 3},
+	}
+	opts.Roots.AddCert(r)
+
+	_, err := c.buildChains([]*Certificate{r}, nil, opts)
+	if _, ok := err.(UnknownAuthorityError); !ok {
+		t.Fatalf("buildChains returned unexpected error, got: %v, want %v", err, UnknownAuthorityError{})
+	}
+}