More than 100 charities have reported serious incidents to the industry regulator as a result of the cyber attacks on the software company Blackbaud.
The Charity Commission said 105 charities had been affected, but it was unable to disclose the details of specific reports.
The regulator previously stated in July that 33 charities had reported being caught up in the ransomware attack, but the numbers have risen significantly since then.
The update comes after the US-based software provider at the centre of the attack admitted, in a disclosure to the US Securities and Exchange Commission, that some financial information may have also been stolen.
The technology company originally told affected customers that only names, addresses, email addresses and telephone numbers had been stolen.
Blackbaud has already apologised for the breach and said it has made changes to avoid a similar attack in the future.
It also paid the ransom in an attempt to ensure that data would not be made publicly available or shared elsewhere.
Blackbaud is one of the biggest providers of fundraising, financial management and supporter management software to the UK charity sector.
A commission spokesperson said: “We are unable to disclose details of specific reports we have received from individual charities, but in total 105 charities have now reported serious incidents to us in relation to the Blackbaud breach, in line with our guidance on reporting serious incidents.”
“We are continuing to assess information in line with our regulatory framework to ensure the charities have responded appropriately.”
The regulator also highlighted some recently published information about its upcoming Charity Fraud Awareness Week, which it said will help charities with their fraud awareness and prevention.