A council has written to more than 7,000 individuals whose data was compromised.
In response to the problem with the outsourcing contractor Capita, Colchester City Council reported that it had sent 3,488 emails and 3,861 letters to people on Friday.
The contractor had been in charge of overseeing the council's benefits program and council tax audits for six years.
The data is safe and no longer accessible, according to Capita. ".
According to Colchester City Council, the data has been protected.
The council claimed Capita reported a "security issue" when names and addresses of individuals were discovered "on its unsecured data storage area.".
There were no hacked bank details.
93 residents were impacted, according to Rochford District Council, one of eight local authorities involved, which was contacted by the BBC. .
Capita stated: "Our clients' information security and privacy are of the utmost importance to us. ".
According to Colchester City Council, Capita has taken steps to secure the data and has confirmed that there is no current proof of anyone accessing the data intentionally. ".
It expressed extreme disappointment that Capita had not upheld the high security standards it demands of its suppliers.
The UK's watchdog for information and personal data, the Information Commissioner's Office, stated that it was aware of two incidents involving a cyberattack at Capita in March 2023 and the use of storage that was open to the public. .
A spokesperson stated, "We are receiving a significant number of reports from organizations directly affected by these incidents, and we are currently conducting investigations.
. "
