Dear members,

We would like to inform you that a data breach has occurred at AllUnited, the system used by Walhalla and NVLTB to manage their membership records. Unfortunately, your personal data has also been compromised. We sincerely regret this. In this message, we explain what happened and what you should be aware of.

What happened?
On Monday evening, 9 November 2026, an unknown attacker exploited a vulnerability in AllUnited’s software. This allowed them to copy data from the database. The breach affected data belonging to all clubs and associations that use AllUnited, including our club.

AllUnited discovered the breach on 10 November and fixed the vulnerability on the same day.

What personal data was involved?
The following information may have been accessed:
– Name, address and place of residence
– Email address and telephone number
– Date and place of birth and bank account number (IBAN)
– If you have an AllUnited account: your login credentialsOther information in your membership record, such as membership number, team, role or notes

What are the potential consequences?
Criminals could use this information to deceive or mislead you. For example, they may:
– Send messages that appear to come from NVLTB, Walhalla or AllUnited;Ask you to pay membership fees, a fine or another amount via a link;
– Send you a payment request;
– Impersonate you using your personal information.

Although an IBAN alone cannot be used to withdraw money from your bank account, criminals may use this information to create highly convincing phishing messages.

Please therefore be extra vigilant when receiving messages requesting personal information, login credentials or payments.

What can you do?
Be cautious when receiving payment requests. Always check whether they are genuine before making a payment.

Change your password if you use the same password for AllUnited, the ClubApp or our membership portal on other websites or services.

Below, you will find examples of what fraudulent messages might look like.

What are we and AllUnited doing?
– AllUnited has fixed the vulnerability.
– AllUnited is resetting all passwords and introducing additional security measures and checks.
– We have reported the data breach to the Dutch Data Protection Authority (Autoriteit Persoonsgegevens).
– As an additional precaution, our club will temporarily stop sending payment requests by email.

Questions?

Please contact the board at voorzitter@gtc-walhalla.nl.

We are very shocked and sorry that this has happened. We will keep you informed if any new information becomes available.

Kind regards,
Benjamin Slotboom, Chair Walhalla