Companies House WebFiling Security Issue: What Happened and What to Do Now

If you run a UK limited company, you may have already received an email from Companies House about a security issue affecting its WebFiling service. Here is a clear summary of what happened, what it means for your company, and what you should do right now.

What happened?

Companies House disclosed that a technical issue existed in its WebFiling service between October 2025 and 13 March 2026. During this time, a logged-in user could potentially have viewed or amended another company's details without permission. Access was limited to registered WebFiling users only and the issue was not accessible to the general public. 

Once identified, Companies House took WebFiling offline promptly to resolve it.

What was not affected?

The good news is that Companies House believes the scope of this issue was limited. Any access would have been to individual company records only, viewed one at a time by a registered WebFiling user, meaning large-scale or systematic data extraction would not have been possible.

• According to its official statement:
• Passwords were not compromised
• No identity verification data, such as passport information, was accessed
• No existing filed documents, such as accounts or confirmation statements, could have been altered
• If you had applied to protect your personal details under the Companies Act 2006, Companies House has confirmed your information was not affected by this issue

What data may have been affected?

According to Companies House, some information from individual company records could have been visible to other logged-in WebFiling users. This includes directors' and PSCs' (Persons with Significant Control) dates of birth, residential addresses, and company registered email addresses. 

There is also a possibility that unauthorised filings may have been made on another company's record, such as accounts submissions or changes of director.

How serious is this?

At this stage, Companies House has said it has no confirmed reports of data having been accessed or changed without permission. However, it has also said its investigation is ongoing and it will provide further updates as its work progresses.

What is Companies House doing about it?

• According to its official statement, Companies House has:
• Reported the incident to the Information Commissioner's Office (ICO) and the National Cyber Security Centre (NCSC)
• Emailed every company's registered email address to explain how to check their details
• Said it will take firm action if it finds evidence that anyone used the vulnerability to access or change another company's details without authorisation
• Committed to publishing further updates as its investigation continues

What should you do now?

Companies House is asking all companies to take the following steps as a precaution.

1. Check your registered details and filing history

Log in to WebFiling or visit the Find and Update Company Information service on GOV.UK to check your company's details. Look through your filing history to make sure everything appears as you would expect. Pay particular attention to director details, registered office address, and any recent filings.

2. Report anything unexpected to Companies House

If anything looks incorrect or unfamiliar, Companies House has asked companies to contact it at [email protected], using 'WebFiling issue' in the subject heading, and to include evidence describing the concern along with your company name and number.

Going further: protecting your company against fraud

This incident is a reminder that company fraud is a real risk for UK businesses of all sizes. Unauthorised changes to director details, registered addresses, or company filings can be used as part of wider fraud attempts, and they are not always easy to spot quickly without the right monitoring in place.

Companies MadeSimple offers a Company Fraud Protection service designed to help you monitor your company's details and receive alerts if anything changes. It is a straightforward way to keep an eye on your company's record and act quickly if something does not look right.

Where to find the latest updates

Companies House has said it will continue to publish updates as its investigation progresses. You can find the latest guidance on GOV.UK by searching for the official Companies House statement on the WebFiling security issue.

In the meantime, checking your company details now is a sensible step, whatever the outcome of the investigation turns out to be.

This article is based on information published by Companies House as of March 2026. It is for general information only and does not constitute legal, tax, or data protection advice. The situation described is subject to ongoing investigation and may change. For the latest official guidance, visit GOV.UK or the Companies House WebFiling issue updates page. If you are concerned about your company's data or filing history, contact Companies House directly or speak to a qualified professional.