diff --git a/library/x509parse.c b/library/x509parse.c
index 919be65..7d88a0c 100644
--- a/library/x509parse.c
+++ b/library/x509parse.c
@@ -1584,7 +1584,7 @@
 
     pathlen = 1;
 
-    while( cur->version != 0 )
+    while( cur != NULL && cur->version != 0 )
     {
         if( cur->ca_istrue == 0 ||
             crt->issuer_raw.len != cur->subject_raw.len ||
@@ -1612,7 +1612,7 @@
     /*
      * Atempt to validate topmost cert with our CA chain.
      */
-    while( trust_ca->version != 0 )
+    while( trust_ca != NULL && trust_ca->version != 0 )
     {
         if( crt->issuer_raw.len != trust_ca->subject_raw.len ||
             memcmp( crt->issuer_raw.p, trust_ca->subject_raw.p,