diff --git a/ChangeLog b/ChangeLog
index 6995003..9ce5b83 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,6 +18,7 @@
    * Forbid change of server certificate during renegotiation to prevent
      "triple handshake" attack when authentication mode is optional (the
      attack was already impossible when authentication is required).
+   * Check notBefore timestamp of certificates and CRLs from the future.
 
 Bugfix
    * ecp_gen_keypair() does more tries to prevent failure because of
diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 1520a7c..008e795e 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -78,6 +78,8 @@
 #define BADCERT_MISSING             0x40  /**< Certificate was missing. */
 #define BADCERT_SKIP_VERIFY         0x80  /**< Certificate verification was skipped. */
 #define BADCERT_OTHER             0x0100  /**< Other reason (can be used by verify callback) */
+#define BADCERT_FUTURE            0x0200  /**< The certificate validity starts in the future. */
+#define BADCRL_FUTURE             0x0400  /**< The CRL is from the future */
 /* \} name */
 /* \} addtogroup x509_module */
 
diff --git a/library/x509_crt.c b/library/x509_crt.c
index d18e117..4668cdf 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1255,6 +1255,9 @@
         if( x509_time_expired( &crl_list->next_update ) )
             flags |= BADCRL_EXPIRED;
 
+        if( x509_time_future( &crl_list->this_update ) )
+            flags |= BADCRL_FUTURE;
+
         /*
          * Check if certificate is revoked
          */
@@ -1340,6 +1343,9 @@
     if( x509_time_expired( &child->valid_to ) )
         *flags |= BADCERT_EXPIRED;
 
+    if( x509_time_future( &child->valid_from ) )
+        *flags |= BADCERT_FUTURE;
+
     /*
      * Child is the top of the chain. Check against the trust_ca list.
      */
@@ -1420,6 +1426,9 @@
         if( x509_time_expired( &trust_ca->valid_to ) )
             ca_flags |= BADCERT_EXPIRED;
 
+        if( x509_time_future( &trust_ca->valid_from ) )
+            ca_flags |= BADCERT_FUTURE;
+
         if( NULL != f_vrfy )
         {
             if( ( ret = f_vrfy( p_vrfy, trust_ca, path_cnt + 1, &ca_flags ) ) != 0 )
@@ -1451,8 +1460,8 @@
     x509_crt *grandparent;
     const md_info_t *md_info;
 
-    if( x509_time_expired( &child->valid_to ) )
-        *flags |= BADCERT_EXPIRED;
+    if( x509_time_future( &child->valid_from ) )
+        *flags |= BADCERT_FUTURE;
 
     md_info = md_info_from_type( child->sig_md );
     if( md_info == NULL )
diff --git a/tests/data_files/server5-expired.crt b/tests/data_files/server5-expired.crt
new file mode 100644
index 0000000..d726e5c
--- /dev/null
+++ b/tests/data_files/server5-expired.crt
@@ -0,0 +1,14 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 166be68..6f2c2d3 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -194,22 +194,38 @@
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_ECP_C
 x509_time_future:"data_files/test-ca2.crt":"valid_to":1
 
-X509 Certificate verification #1 (Revoked Cert, Expired CRL)
+X509 Certificate verification #1 (Revoked Cert, Expired CRL, no CN)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
 x509_verify:"data_files/server1.crt":"data_files/test-ca.crt":"data_files/crl_expired.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCRL_EXPIRED:"NULL"
 
+X509 Certificate verification #1a (Revoked Cert, Future CRL, no CN)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server6.crt":"data_files/test-ca2.crt":"data_files/crl-future.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCRL_FUTURE:"NULL"
+
 X509 Certificate verification #2 (Revoked Cert, Expired CRL)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
 x509_verify:"data_files/server1.crt":"data_files/test-ca.crt":"data_files/crl_expired.pem":"PolarSSL Server 1":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCRL_EXPIRED:"NULL"
 
-X509 Certificate verification #3 (Revoked Cert, Expired CRL, CN Mismatch)
+X509 Certificate verification #2a (Revoked Cert, Future CRL)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server6.crt":"data_files/test-ca2.crt":"data_files/crl-future.pem":"localhost":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCRL_FUTURE:"NULL"
+
+X509 Certificate verification #3 (Revoked Cert, Future CRL, CN Mismatch)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
 x509_verify:"data_files/server1.crt":"data_files/test-ca.crt":"data_files/crl_expired.pem":"PolarSSL Wrong CN":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCRL_EXPIRED | BADCERT_CN_MISMATCH:"NULL"
 
+X509 Certificate verification #3a (Revoked Cert, Expired CRL, CN Mismatch)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server6.crt":"data_files/test-ca2.crt":"data_files/crl-future.pem":"Wrong CN":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCRL_FUTURE | BADCERT_CN_MISMATCH:"NULL"
+
 X509 Certificate verification #4 (Valid Cert, Expired CRL)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
 x509_verify:"data_files/server2.crt":"data_files/test-ca.crt":"data_files/crl_expired.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCRL_EXPIRED:"NULL"
 
+X509 Certificate verification #4a (Revoked Cert, Future CRL)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server5.crt":"data_files/test-ca2.crt":"data_files/crl-future.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCRL_FUTURE:"NULL"
+
 X509 Certificate verification #5 (Revoked Cert)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
 x509_verify:"data_files/server1.crt":"data_files/test-ca.crt":"data_files/crl.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED:"NULL"
@@ -223,8 +239,16 @@
 x509_verify:"data_files/server1.crt":"data_files/test-ca.crt":"data_files/crl.pem":"PolarSSL Wrong CN":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_REVOKED | BADCERT_CN_MISMATCH:"NULL"
 
 X509 Certificate verification #8 (Valid Cert)
-depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15
-x509_verify:"data_files/server2.crt":"data_files/test-ca.crt":"data_files/crl.pem":"NULL":0:0:"NULL"
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server5.crt":"data_files/test-ca2.crt":"data_files/crl-ec-sha1.pem":"NULL":0:0:"NULL"
+
+X509 Certificate verification #8a (Expired Cert)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server5-expired.crt":"data_files/test-ca2.crt":"data_files/crl-ec-sha1.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_EXPIRED:"NULL"
+
+X509 Certificate verification #8b (Future Cert)
+depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_ECP_C:
+x509_verify:"data_files/server5-future.crt":"data_files/test-ca2.crt":"data_files/crl-ec-sha1.pem":"NULL":POLARSSL_ERR_X509_CERT_VERIFY_FAILED:BADCERT_FUTURE:"NULL"
 
 X509 Certificate verification #9 (Not trusted Cert)
 depends_on:POLARSSL_PEM_PARSE_C:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_PKCS1_V15