Companies House WebFiling security breach update and recommended actions

Why is it relevant?

Companies House confirmed that, in limited circumstances, a logged-in WebFiling user in possession of their authorised access code could potentially have viewed or changed certain details of another company. This scenario would only have arisen after a specific set of actions was performed. Importantly, the WebFiling was not accessible to the general public during this security breach.

Who does it affect?

Information not normally published on the public register may have been visible to other logged in users, including directors’ dates of birth, residential addresses and company email addresses. It may also have been possible for unauthorised filings (for example, accounts or changes of directors) to have been submitted on another company’s record.

What do you need to know?

Companies House has confirmed that:

• passwords were not compromised;
• identity verification data (such as passport details) was not accessed; and
• existing filed documents (including accounts and confirmation statements) could not have been altered

What Companies House is doing?

The incident has been reported to the Information Commissioner’s Office (ICO) and the National Cyber Security Centre. Companies House is analysing its systems for anomalies and is emailing companies at their registered email addresses with further guidance.

What have we done for our clients that are using our annual company secretarial compliance service?

As part of our company secretarial service, we monitor each of our client company’s filings at Companies House and receive email notifications when filings are accepted. We have not identified any unexpected filings for any of our company secretarial clients in the period from October 2025 to 16 March 2026.

What should you do next?

If we are not providing the company secretarial service to your company we recommend that you take the following steps:

• Review your company’s details on the Companies House register to check whether anything appears incorrect. Use the link below to access the register and type the company’s full name or the registered number. Search the register
• Once you access the company’s page, go to filing history tab and review the company’s filings submitted from October 2025 to date and check whether any unauthorised filings have been made in this period.
• If you identify any unexpected or incorrect filings, raise a complaint directly with Companies House via enquiries@companieshouse.gov.uk and retain any supporting evidence.
• If you experience any filing difficulties via WebFiling, retain the screen shots of any error messages, ensure that these show the time and date when the filing was attempted. If a filing deadline is missed due to the filing error messages, Companies House will take these into account. Submit the filing as soon as the WebFiling service is available.

At this stage, Companies House has stated that it has no reports of data having been accessed or changed without permission, but their investigation is ongoing and the Chief Executive Officer has asked all companies to carry out these checks as a precaution.

We are monitoring developments closely and will update you if further guidance is issued. If you would like us to assist with a review of your Companies House record or liaise with Companies House on your behalf, please let us know.

Here is the link to the official announcement from Companies House: Update on Companies House WebFiling security issue – GOV.UK

Contact us

If you would like to discuss the above matter further, or to confirm how this impacts your company, please get in touch with your usual Blick Rothenberg contact or Vesna Sowden, using the form below, to see how we can assist with any future planning.