diff --git a/library/x509_crt.c b/library/x509_crt.c
index d101bc7..b2c19db 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1687,7 +1687,7 @@
 
     if( p + len >= end )
     {
-        mbedtls_platform_zeroize( other_name, sizeof( other_name ) );
+        mbedtls_platform_zeroize( other_name, sizeof( *other_name ) );
         return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
     }
@@ -1709,7 +1709,7 @@
 
     if( p + len >= end )
     {
-        mbedtls_platform_zeroize( other_name, sizeof( other_name ) );
+        mbedtls_platform_zeroize( other_name, sizeof( *other_name ) );
         return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
     }
@@ -1725,7 +1725,7 @@
     if( p != end )
     {
         mbedtls_platform_zeroize( other_name,
-                                  sizeof( other_name ) );
+                                  sizeof( *other_name ) );
         return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
     }