diff --git a/library/x509_crl.c b/library/x509_crl.c
index b0f39d4..cb1e8c4 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -107,6 +107,9 @@
 {
     int ret;
 
+    if( *p == end )
+        return( 0 );
+
     /*
      * crlExtensions           [0]  EXPLICIT Extensions OPTIONAL
      *                              -- if present, version MUST be v2
@@ -119,6 +122,8 @@
         return( ret );
     }
 
+    end = ext->p + ext->len;
+
     while( *p < end )
     {
         /*