diff --git a/ChangeLog b/ChangeLog
index 2f0116b..9bf6a17 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS 2.y.z released YYYY-MM-DD
+
+Changes
+   * Certificate verification functions now set flags to -1 in case the full
+     chain was not verified due to an internal error (including in the verify
+     callback) or chain length limitations.
+
 = mbed TLS 2.5.1 released 2017-06-21
 
 Security
diff --git a/library/x509_crt.c b/library/x509_crt.c
index d86857d..ee5f27e 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -2202,11 +2202,14 @@
     mbedtls_x509_sequence *cur = NULL;
     mbedtls_pk_type_t pk_type;
 
-    if( profile == NULL )
-        return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
-
     *flags = 0;
 
+    if( profile == NULL )
+    {
+        ret = MBEDTLS_ERR_X509_BAD_INPUT_DATA;
+        goto exit;
+    }
+
     if( cn != NULL )
     {
         name = &crt->subject;
@@ -2280,7 +2283,7 @@
         ret = x509_crt_verify_top( crt, parent, ca_crl, profile,
                                    pathlen, selfsigned, flags, f_vrfy, p_vrfy );
         if( ret != 0 )
-            return( ret );
+            goto exit;
     }
     else
     {
@@ -2295,17 +2298,24 @@
             ret = x509_crt_verify_child( crt, parent, trust_ca, ca_crl, profile,
                                          pathlen, selfsigned, flags, f_vrfy, p_vrfy );
             if( ret != 0 )
-                return( ret );
+                goto exit;
         }
         else
         {
             ret = x509_crt_verify_top( crt, trust_ca, ca_crl, profile,
                                        pathlen, selfsigned, flags, f_vrfy, p_vrfy );
             if( ret != 0 )
-                return( ret );
+                goto exit;
         }
     }
 
+exit:
+    if( ret != 0 )
+    {
+        *flags = (uint32_t) -1;
+        return( ret );
+    }
+
     if( *flags != 0 )
         return( MBEDTLS_ERR_X509_CERT_VERIFY_FAILED );
 
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 9d3108a..6df5298 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -1204,7 +1204,7 @@
 
 X509 CRT verify long chain (max intermediate CA + 1)
 depends_on:MBEDTLS_SHA256_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED
-mbedtls_x509_crt_verify_max:"data_files/dir-maxpath/00.crt":"data_files/dir-maxpath":MBEDTLS_X509_MAX_INTERMEDIATE_CA+1:MBEDTLS_ERR_X509_CERT_VERIFY_FAILED:0
+mbedtls_x509_crt_verify_max:"data_files/dir-maxpath/00.crt":"data_files/dir-maxpath":MBEDTLS_X509_MAX_INTERMEDIATE_CA+1:MBEDTLS_ERR_X509_CERT_VERIFY_FAILED:-1
 
 X509 CRT verify chain #1 (zero pathlen intermediate)
 depends_on:MBEDTLS_SHA256_C:MBEDTLS_RSA_C