MySQL Bugs: #25802: a privilege was remoked by no one.

Bug #25802	a privilege was remoked by no one.
Submitted:	23 Jan 2007 20:52	Modified:	24 Feb 2007 2:13
Reporter:	Xin Li	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Server: Security: Privileges	Severity:	S1 (Critical)
Version:	5.0.19	OS:	Linux (Linux)
Assigned to:		CPU Architecture:	Any
Tags:	mysql.db, privilege

Description:
Today, we got a very weird issue: a row in privilege table was deleted on our production server. When that happened, we were working on a separate staging server and try to grant 'lock tables' privilege to an user, and "show grants" for the "same" user on the production server. Here is what we got from binlog:

# at 2887255
#070123 10:49:03 server id 1  end_log_pos 2887473       Query   thread_id=228847        exec_time=0     error_code=0
SET TIMESTAMP=1169567343;
/*!\C utf8 */;
SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=8;
DELETE FROM mysql.db WHERE Select_priv='N' AND Insert_priv='N' AND Update_priv='N' AND Delete_priv='N' AND Create_priv='N' AND Drop_priv='N' AND Grant_priv='N';
# at 2887473
#070123 10:49:03 server id 1  end_log_pos 2887548       Query   thread_id=228847        exec_time=0     error_code=0
SET TIMESTAMP=1169567343;
FLUSH PRIVILEGES;

So, you can look at the delete statement, it doesn't like a human being's typing. Did you see any thing similar before?

How to repeat:
don't know how to repeat.

Thank you for the bug report. Could you please try the latest released
version, 5.0.19 is pretty older. Please re-open this bug report if still
the issue exists. Thanks in advance.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".