Companies House have issued a statement regarding a security issue in which data from individual companies, not usually published on the Companies House register, may have been visible to other logged-in users. An investigation indicates the issue was introduced when the WebFiling system was updated in October 2025 and means that a logged-in user could potentially access and change some elements of another company’s details without their consent after performing a specific set of actions.
WebFiling was closed from 1.30pm on Friday 13 March while the issue was investigated. WebFiling was independently tested and was online as of 9am on Monday 16 March.
Data that may have been affected
Affected data includes:
- dates of birth
- residential addresses
- company email addresses
It may also have been possible to make unauthorised filings on another company’s records, this includes accounts or changes of directors.
Companies House have not received any reports of data having been accessed or changed without permission at this stage. However the investigation is ongoing, and further updates will provided as work progresses.
Data that was not affected
Companies House have stated that the following information was not affected:
- Passwords were not compromised.
- No data used as part of the identity verification process, such as passport information, was compromised.
- No existing filed documents, such as accounts or confirmation statements, could have been altered.
Action being taken by Companies House
Companies House have reported the incident to the Information Commissioners Office (ICO) and the National Cyber Security Centre (NCSC).
Companies House are analysing their data to identify any anomalies and will be emailing the registered email for every company to explain how to check their details and what steps to take if they have any concerns.
Action to be taken by companies
All companies are being asked to check their registered details and filing history to make sure everything appears correct.
Concerns should be raised by using the online complaints form, and evidence included to describe the concern.
Further information
For further information on this issue, please see the statement issued by Andy Kings, CEO of Companies House.