Shuffle a column between rows and update

For test purpose, I have the following table:

CREATE TABLE DANILO.TESTE2(
CPF VARCHAR2(11),
NOME VARCHAR2(100));

insert into danilo.teste2 values ('93434433443','Sousa');
insert into danilo.teste2 values ('54545454545','Ferreira');
insert into danilo.teste2 values ('99393201832','Cavalcante');
insert into danilo.teste2 values ('13902939392','Silva');

Then, I've used this answer to Shuffle cpf column data, and it's working fine for my case.

select t2.cpf, t.nome
from (select t.*, rownum as seqnum from danilo.teste2 t) t join
     (select t.*, row_number() over (order by dbms_random.value) as seqnum from danilo.teste2 t) t2 -- TABELA QUE EMBARALHA
     on t.seqnum = t2.seqnum;

But how can I shuffling it and update all cpf rows?

I've tried something like it:

     MERGE INTO danilo.teste2 t1
USING (
    SELECT 
        cpf,
        ROW_NUMBER() OVER (ORDER BY DBMS_RANDOM.VALUE) AS random_order
    FROM danilo.teste2
) shuffled_data
ON (1 = 1)
WHEN MATCHED THEN
    UPDATE SET t1.cpf = shuffled_data.cpf;

but I got ORA-30926: unable to get a stable set of rows in the source tables

What I need is to Shuffle cpf column data to "mask" it, but leaving the real data.

Just use your query (or something similar correlating on the ROWID pseudo-column) in the USING clause of a MERGE statement:

MERGE INTO danilo.teste2 dst
USING (
  select t.rid,
         t2.nome
  from   (
           SELECT ROWNUM AS rn,
                  ROWID AS rid
           FROM   danilo.teste2
         ) t
         INNER JOIN (
           SELECT nome,
                  ROW_NUMBER() OVER (ORDER BY DBMS_RANDOM.VALUE) AS rn
           FROM   danilo.teste2
         ) t2
         ON t.rn = t2.rn
) src
ON (src.rid = dst.ROWID)
WHEN MATCHED THEN
  UPDATE SET nome = src.nome;

Then, after the MERGE statement, the table may (randomly) contain:

fiddle