Companies House warns about WebFiling security issue
March 19, 2026
Companies House has recently confirmed a security issue affecting its WebFiling service, and we want to ensure our clients are fully informed and reassured.
On 18 March 2026, Companies House notified registered users that it had identified a flaw in its WebFiling system on 13 March 2026. The issue relates to a system update introduced in October 2025 as part of the move towards enhanced identity verification.
What was the issue?
According to Companies House, the flaw may have allowed individuals with an existing WebFiling account, in certain circumstances, to:
- Submit filings for companies they were not authorised to act for
- Access limited non-public information, including:
- The full date of birth (including day) for directors and Persons with Significant Control (PSCs)
- Residential addresses for directors and PSCs
- Company registered email addresses
Importantly, Companies House has confirmed that:
- Passwords were not compromised
- Identity documents (such as passports or driving licences) were not accessed
- Previously filed documents could not be altered
What is happening now?
Companies House is currently analysing its data to determine whether any unauthorised filings have taken place as a result of this issue. As a precaution, all companies are being encouraged to review their records and report anything unusual.
Our position
As part of our ongoing company secretarial monitoring, Alexander Knight & Co has not identified any suspicious or unauthorised filings in relation to our clients to date.
We are continuing to monitor the situation closely and will provide further updates if required.
Murray Patt, founder of Alexander Knight & Co, said:
“This is clearly a concerning development, but it’s important to keep it in perspective. At this stage, there is no indication of widespread misuse, and safeguards remain in place.
“Our role is to stay close to the detail, monitor our clients’ records carefully and act quickly if anything looks out of the ordinary. We would encourage all clients to remain vigilant, but also reassured that we are actively overseeing this on their behalf.”
What should you do?
At this stage, we recommend:
- Keeping an eye on your Companies House filings and records
- Flagging any unexpected changes or unfamiliar filings immediately