diff --git a/library/rsa.c b/library/rsa.c
index 56fd7920f9..6b720a4f90 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1369,9 +1369,6 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
         return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
 
     hlen = md_get_size( md_info );
-    if( siglen < hlen + 2 )
-        return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
-    hash_start = buf + siglen - hlen - 1;
 
     memset( zeros, 0, 8 );
 
@@ -1390,6 +1387,10 @@ int rsa_rsassa_pss_verify_ext( rsa_context *ctx,
     if( buf[0] >> ( 8 - siglen * 8 + msb ) )
         return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
 
+    if( siglen < hlen + 2 )
+        return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
+    hash_start = p + siglen - hlen - 1;
+
     md_init( &md_ctx );
     if( ( ret = md_init_ctx( &md_ctx, md_info ) ) != 0 )
     {
diff --git a/tests/suites/test_suite_pkcs1_v21.data b/tests/suites/test_suite_pkcs1_v21.data
index b396c642a8..1c41137487 100644
--- a/tests/suites/test_suite_pkcs1_v21.data
+++ b/tests/suites/test_suite_pkcs1_v21.data
@@ -817,7 +817,7 @@ pkcs1_rsassa_pss_verify_ext:512:16:"00b076d23250816f9aab02307e452b97f0cae7598369
 
 RSASSA-PSS verify ext, 521-bit key, SHA-512, empty salt, bad signature
 depends_on:POLARSSL_SHA512_C
-pkcs1_rsassa_pss_verify_ext:521:16:"0131b69860f3cb9bf85ea358fdf2bd2990f1b77a80d6a4fdf817a43dd896bdf7dd26af8ac0237f526e0d33b105c971fdbd4ffa9ece99fc469f31ecf429e8f562c1c3":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:0:"":"00471794655837da498cbf27242807b40593a353c707eb22fd2cc5a3259e728ac4f1df676043eeec8e16c1175b3d9ac8cae72ec1d5772dd69de71c5677f19031568e":POLARSSL_ERR_RSA_INVALID_PADDING:POLARSSL_ERR_RSA_INVALID_PADDING
+pkcs1_rsassa_pss_verify_ext:521:16:"0131b69860f3cb9bf85ea358fdf2bd2990f1b77a80d6a4fdf817a43dd896bdf7dd26af8ac0237f526e0d33b105c971fdbd4ffa9ece99fc469f31ecf429e8f562c1c3":16:"010001":POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:POLARSSL_MD_SHA512:0:"":"00471794655837da498cbf27242807b40593a353c707eb22fd2cc5a3259e728ac4f1df676043eeec8e16c1175b3d9ac8cae72ec1d5772dd69de71c5677f19031568e":POLARSSL_ERR_RSA_BAD_INPUT_DATA:POLARSSL_ERR_RSA_BAD_INPUT_DATA
 
 RSASSA-PSS verify ext, all-zero padding, automatic salt length
 depends_on:POLARSSL_SHA256_C