diff --git a/src/crypto/x509/verify.go b/src/crypto/x509/verify.go
index 29345a1..67f9ff5 100644
--- a/src/crypto/x509/verify.go
+++ b/src/crypto/x509/verify.go
@@ -191,6 +191,10 @@
 
 // isValid performs validity checks on the c.
 func (c *Certificate) isValid(certType int, currentChain []*Certificate, opts *VerifyOptions) error {
+	if len(c.UnhandledCriticalExtensions) > 0 {
+		return UnhandledCriticalExtension{}
+	}
+
 	if len(currentChain) > 0 {
 		child := currentChain[len(currentChain)-1]
 		if !bytes.Equal(child.RawIssuer, c.RawSubject) {
@@ -279,10 +283,6 @@
 		return c.systemVerify(&opts)
 	}
 
-	if len(c.UnhandledCriticalExtensions) > 0 {
-		return nil, UnhandledCriticalExtension{}
-	}
-
 	if opts.Roots == nil {
 		opts.Roots = systemRootsPool()
 		if opts.Roots == nil {
diff --git a/src/crypto/x509/verify_test.go b/src/crypto/x509/verify_test.go
index 15c40914..6366134 100644
--- a/src/crypto/x509/verify_test.go
+++ b/src/crypto/x509/verify_test.go
@@ -263,6 +263,30 @@
 
 		errorCallback: expectSubjectIssuerMismatcthError,
 	},
+	{
+		// Test that unknown critical extensions in a leaf cause a
+		// verify error.
+		leaf:          criticalExtLeafWithExt,
+		dnsName:       "example.com",
+		intermediates: []string{criticalExtIntermediate},
+		roots:         []string{criticalExtRoot},
+		currentTime:   1486684488,
+		systemSkip:    true,
+
+		errorCallback: expectUnhandledCriticalExtension,
+	},
+	{
+		// Test that unknown critical extensions in an intermediate
+		// cause a verify error.
+		leaf:          criticalExtLeaf,
+		dnsName:       "example.com",
+		intermediates: []string{criticalExtIntermediateWithExt},
+		roots:         []string{criticalExtRoot},
+		currentTime:   1486684488,
+		systemSkip:    true,
+
+		errorCallback: expectUnhandledCriticalExtension,
+	},
 }
 
 func expectHostnameError(t *testing.T, i int, err error) (ok bool) {
@@ -330,6 +354,14 @@
 	return true
 }
 
+func expectUnhandledCriticalExtension(t *testing.T, i int, err error) (ok bool) {
+	if _, ok := err.(UnhandledCriticalExtension); !ok {
+		t.Errorf("#%d: error was not an UnhandledCriticalExtension: %s", i, err)
+		return false
+	}
+	return true
+}
+
 func certificateFromPEM(pemBytes string) (*Certificate, error) {
 	block, _ := pem.Decode([]byte(pemBytes))
 	if block == nil {
@@ -1379,3 +1411,67 @@
 4R+gnfLd37FWflMHwztFbVTuNtPOljCX0LN7KcuoXYlr05RhQrmoN7fQHsrZMNLs
 8FVjHdKKu+uPstwd04Uy4BR/H2y1yerN9j/L6ZkMl98iiA==
 -----END CERTIFICATE-----`
+
+const criticalExtRoot = `-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----`
+
+const criticalExtIntermediate = `-----BEGIN CERTIFICATE-----
+MIIBszCCAVmgAwIBAgIJAL2kcGZKpzVqMAoGCCqGSM49BAMCMB0xDDAKBgNVBAoT
+A09yZzENMAsGA1UEAxMEUm9vdDAeFw0xNTAxMDEwMDAwMDBaFw0yNTAxMDEwMDAw
+MDBaMCUxDDAKBgNVBAoTA09yZzEVMBMGA1UEAxMMSW50ZXJtZWRpYXRlMFkwEwYH
+KoZIzj0CAQYIKoZIzj0DAQcDQgAESqVq92iPEq01cL4o99WiXDc5GZjpjNlzMS1n
+rk8oHcVDp4tQRRQG3F4A6dF1rn/L923ha3b0fhDLlAvXZB+7EKN6MHgwDgYDVR0P
+AQH/BAQDAgIEMB0GA1UdJQQWMBQGCCsGAQUFBwMBBggrBgEFBQcDAjAPBgNVHRMB
+Af8EBTADAQH/MBkGA1UdDgQSBBCMGmiotXbbXVd7H40UsgajMBsGA1UdIwQUMBKA
+EEA31wH7QC+4HH5UBCeMWQEwCgYIKoZIzj0EAwIDSAAwRQIhAOhhNRb6KV7h3wbE
+cdap8bojzvUcPD78fbsQPCNw1jPxAiBOeAJhlTwpKn9KHpeJphYSzydj9NqcS26Y
+xXbdbm27KQ==
+-----END CERTIFICATE-----`
+
+const criticalExtLeafWithExt = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+const criticalExtIntermediateWithExt = `-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`
+
+const criticalExtLeaf = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
diff --git a/src/crypto/x509/x509_test.go b/src/crypto/x509/x509_test.go
index b085dad..5e81e9f 100644
--- a/src/crypto/x509/x509_test.go
+++ b/src/crypto/x509/x509_test.go
@@ -518,74 +518,6 @@
 	}
 }
 
-func TestUnknownCriticalExtension(t *testing.T) {
-	priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
-	if err != nil {
-		t.Fatalf("Failed to generate ECDSA key: %s", err)
-	}
-
-	oids := []asn1.ObjectIdentifier{
-		// This OID is in the PKIX arc, but unknown.
-		{2, 5, 29, 999999},
-		// This is a nonsense, unassigned OID.
-		{1, 2, 3, 4},
-	}
-
-	for _, oid := range oids {
-		template := Certificate{
-			SerialNumber: big.NewInt(1),
-			Subject: pkix.Name{
-				CommonName: "foo",
-			},
-			NotBefore: time.Unix(1000, 0),
-			NotAfter:  time.Now().AddDate(1, 0, 0),
-
-			BasicConstraintsValid: true,
-			IsCA: true,
-
-			KeyUsage:    KeyUsageCertSign,
-			ExtKeyUsage: []ExtKeyUsage{ExtKeyUsageServerAuth},
-
-			ExtraExtensions: []pkix.Extension{
-				{
-					Id:       oid,
-					Critical: true,
-					Value:    nil,
-				},
-			},
-		}
-
-		derBytes, err := CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
-		if err != nil {
-			t.Fatalf("failed to create certificate: %s", err)
-		}
-
-		cert, err := ParseCertificate(derBytes)
-		if err != nil {
-			t.Fatalf("Certificate with unknown critical extension was not parsed: %s", err)
-		}
-
-		roots := NewCertPool()
-		roots.AddCert(cert)
-
-		// Setting Roots ensures that Verify won't delegate to the OS
-		// library and thus the correct error should always be
-		// returned.
-		_, err = cert.Verify(VerifyOptions{Roots: roots})
-		if err == nil {
-			t.Fatal("Certificate with unknown critical extension was verified without error")
-		}
-		if _, ok := err.(UnhandledCriticalExtension); !ok {
-			t.Fatalf("Error was %#v, but wanted one of type UnhandledCriticalExtension", err)
-		}
-
-		cert.UnhandledCriticalExtensions = nil
-		if _, err = cert.Verify(VerifyOptions{Roots: roots}); err != nil {
-			t.Errorf("Certificate failed to verify after unhandled critical extensions were cleared: %s", err)
-		}
-	}
-}
-
 // Self-signed certificate using ECDSA with SHA1 & secp256r1
 var ecdsaSHA1CertPem = `
 -----BEGIN CERTIFICATE-----