diff --git a/ChangeLog b/ChangeLog
index e9b67908f..f7b318eb9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,11 @@ mbed TLS ChangeLog (Sorted per branch, date)
 
 = mbed TLS 2.x branch
 
+Security
+   * Fix potential integer overflow to buffer overflow in
+     mbedtls_rsa_rsaes_pkcs1_v15_encrypt and mbedtls_rsa_rsaes_oaep_encrypt
+     (not triggerable remotely in (D)TLS).
+
 Bugfix
    * Fix bug in mbedtls_mpi_add_mpi() that caused wrong results when the three
      arguments where the same (in-place doubling). Found and fixed by Janos
diff --git a/library/rsa.c b/library/rsa.c
index fba68ddfc..9150e8745 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -529,7 +529,8 @@ 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 );
@@ -595,7 +596,8 @@ int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
 
     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;