diff --git a/ChangeLog b/ChangeLog
index d4cf85b7e..20c8eaf95 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS x.x.x branch released xxxx-xx-xx
+
+Bugfix
+   * Fix output certificate verification flags set by x509_crt_verify_top() when
+     traversing a chain of trusted CA. The issue would cause both flags,
+     BADCERT_NOT_TRUSTED and BADCERT_EXPIRED, to be set when the verification
+     conditions are not met regardless of the cause. Found by Harm Verhagen and
+     inestlerode. #665 #561
+
 = mbed TLS 1.3.18 branch 2016-10-17
 
 Security
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 4b831aed3..a3517f64f 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1775,6 +1775,7 @@ static int x509_crt_verify_top(
     int ca_flags = 0, check_path_cnt;
     unsigned char hash[POLARSSL_MD_MAX_SIZE];
     const md_info_t *md_info;
+    x509_crt *future_past_ca = NULL;
 
     if( x509_time_expired( &child->valid_to ) )
         *flags |= BADCERT_EXPIRED;
@@ -1823,16 +1824,6 @@ static int x509_crt_verify_top(
             continue;
         }
 
-        if( x509_time_expired( &trust_ca->valid_to ) )
-        {
-            continue;
-        }
-
-        if( x509_time_future( &trust_ca->valid_from ) )
-        {
-            continue;
-        }
-
         if( pk_verify_ext( child->sig_pk, child->sig_opts, &trust_ca->pk,
                            child->sig_md, hash, md_info->size,
                            child->sig.p, child->sig.len ) != 0 )
@@ -1840,11 +1831,23 @@ static int x509_crt_verify_top(
             continue;
         }
 
+        if( x509_time_expired( &trust_ca->valid_to ) ||
+            x509_time_future( &trust_ca->valid_from ) )
+        {
+            if( future_past_ca == NULL )
+                future_past_ca = trust_ca;
+            continue;
+        }
+
+        break;
+    }
+
+    if( trust_ca != NULL || ( trust_ca = future_past_ca ) != NULL )
+    {
         /*
          * Top of chain is signed by a trusted CA
          */
         *flags &= ~BADCERT_NOT_TRUSTED;
-        break;
     }
 
     /*
@@ -1864,6 +1867,12 @@ static int x509_crt_verify_top(
         ((void) ca_crl);
 #endif
 
+        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,