diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c
index 0d1c3ec8cb40734f96529dffadffc28d686c22ac..538883c6b83624a02e1fc796a2d6a0dd945d975d 100644
--- a/drivers/i2c/busses/i2c-ismt.c
+++ b/drivers/i2c/busses/i2c-ismt.c
@@ -498,6 +498,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
 		if (read_write == I2C_SMBUS_WRITE) {
 			/* Block Write */
 			dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA:  WRITE\n");
+			if (data->block[0] < 1 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
+				return -EINVAL;
+
 			dma_size = data->block[0] + 1;
 			dma_direction = DMA_TO_DEVICE;
 			desc->wr_len_cmd = dma_size;