diff --git a/library/x509.c b/library/x509.c
index ab105d8..282a951 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -559,16 +559,18 @@
 {
     int ret;
     size_t len;
+    int tag_type;
 
     if( ( end - *p ) < 1 )
         return( POLARSSL_ERR_X509_INVALID_SIGNATURE +
                 POLARSSL_ERR_ASN1_OUT_OF_DATA );
 
-    sig->tag = **p;
+    tag_type = **p;
 
     if( ( ret = asn1_get_bitstring_null( p, end, &len ) ) != 0 )
         return( POLARSSL_ERR_X509_INVALID_SIGNATURE + ret );
 
+    sig->tag = tag_type;
     sig->len = len;
     sig->p = *p;