diff --git a/ChangeLog b/ChangeLog
index d1a60c262..a0ab24668 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,11 @@ mbed TLS ChangeLog (Sorted per branch, date)
 Security
    * Fix missing padding length check in mbedtls_rsa_rsaes_pkcs1_v15_decrypt 
      required by PKCS1 v2.2
+   * Fix a potential integer underflow to buffer overread in 
+     mbedtls_rsa_rsaes_oaep_decrypt. It is not triggerable remotely in
+     SSL/TLS.
+   * Fix potential integer overflow to buffer overflow in
+     mbedtls_rsa_rsaes_pkcs1_v15_encrypt and mbedtls_rsa_rsaes_oaep_encrypt
 
 Bugfix
    * Fix bug in mbedtls_mpi_add_mpi() that caused wrong results when the three
diff --git a/library/rsa.c b/library/rsa.c
index cb32bf46f..4bdf200b5 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -523,7 +523,8 @@ int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx,
     olen = ctx->len;
     hlen = mbedtls_md_get_size( md_info );
 
-    if( olen < ilen + 2 * hlen + 2 )
+    // first comparison checks for overflow
+    if( ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2 )
         return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
     memset( output, 0, olen );
@@ -588,8 +589,9 @@ int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
         return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
     olen = ctx->len;
-
-    if( olen < ilen + 11 )
+    
+    // first comparison checks for overflow
+    if( ilen + 11 < ilen || olen < ilen + 11 )
         return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
     nb_pad = olen - 3 - ilen;
@@ -699,6 +701,12 @@ int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
     if( md_info == NULL )
         return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
+    hlen = mbedtls_md_get_size( md_info );
+
+    // checking for integer underflow
+    if( 2 * hlen + 2 > ilen )
+        return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
     /*
      * RSA operation
      */
@@ -712,8 +720,6 @@ int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
     /*
      * Unmask data and generate lHash
      */
-    hlen = mbedtls_md_get_size( md_info );
-
     mbedtls_md_init( &md_ctx );
     mbedtls_md_setup( &md_ctx, md_info, 0 );