diff --git a/library/rsa.c b/library/rsa.c
index 520f1a2..2703e29 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1394,27 +1394,29 @@
 
     end = p + len;
 
-    // Parse the ASN.1 structure inside the PKCS#1 v1.5 structure
-    //
+    /*
+     * Parse the ASN.1 structure inside the PKCS#1 v1.5 structure.
+     * Insist on 2-byte length tags, to protect against variants of
+     * Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification.
+     */
     p0 = p;
     if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len,
             MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
-
     if( p != p0 + 2 || asn1_len + 2 != len )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
 
+    p0 = p;
     if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len,
             MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
-
-    if( p != p0 + 4 || asn1_len + 6 + hashlen != len )
+    if( p != p0 + 2 || asn1_len + 6 + hashlen != len )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
 
+    p0 = p;
     if( ( ret = mbedtls_asn1_get_tag( &p, end, &oid.len, MBEDTLS_ASN1_OID ) ) != 0 )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
-
-    if( p != p0 + 6 )
+    if( p != p0 + 2 )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
 
     oid.p = p;
@@ -1429,13 +1431,15 @@
     /*
      * assume the algorithm parameters must be NULL
      */
+    p0 = p;
     if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len, MBEDTLS_ASN1_NULL ) ) != 0 )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+    if( p != p0 + 2 )
+        return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
 
     p0 = p;
     if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
-
     if( p != p0 + 2 || asn1_len != hashlen )
         return( MBEDTLS_ERR_RSA_VERIFY_FAILED );