diff --git a/library/psa_crypto_pake.c b/library/psa_crypto_pake.c
index c6f9e89..538df87 100644
--- a/library/psa_crypto_pake.c
+++ b/library/psa_crypto_pake.c
@@ -430,11 +430,26 @@
                 3, /* named_curve */
                 0, 23 /* secp256r1 */
             };
+
+            if (operation->buffer_length + sizeof(ecparameters) > sizeof(operation->buffer)) {
+                return PSA_ERROR_BUFFER_TOO_SMALL;
+            }
+
             memcpy(operation->buffer + operation->buffer_length,
                    ecparameters, sizeof(ecparameters));
             operation->buffer_length += sizeof(ecparameters);
         }
 
+        /*
+         * The core has checked that input_length is smaller than
+         * PSA_PAKE_INPUT_SIZE(PSA_ALG_JPAKE, primitive, step)
+         * where primitive is the JPAKE algorithm primitive and step
+         * the PSA API level input step. Thus no risk of integer overflow here.
+         */
+        if (operation->buffer_length + input_length + 1 > sizeof(operation->buffer)) {
+            return PSA_ERROR_BUFFER_TOO_SMALL;
+        }
+
         /* Write the length byte */
         operation->buffer[operation->buffer_length] = (uint8_t) input_length;
         operation->buffer_length += 1;