Hit by a cyberattack, Belgium's tax authority pulls its portal three days before a deadline

On October 28 at 2:04 p.m., the Federal Public Service (FPS) Finance, Belgium's tax administration, announced that its digital services were under cyberattack. As a precaution, MyMinfin, the online taxpayer portal, was taken offline, along with Tax-on-web, the tax filing tool, and several other services. The full list was not published.

The timing is bad. Several returns were due by October 31 at the latest, including those for certain self-employed income and certain professional income earned abroad, according to Cyberattaque.org.

Was data stolen?

Not at this stage, according to the administration. FPS Finance says it has found no sign of a data leak or theft, and states that this point is being analyzed and monitored. The shutdown "limits the risks" and is meant to give technical teams time to secure the systems, according to RTBF. The administration says it is closely monitoring the situation and is doing everything it can to "restore the affected services as quickly as possible."

Much remains unknown. FPS Finance has not said what kind of attack it is facing, which systems are targeted, or since when. No group has claimed the attack. No ransomware, no encrypted files and no ransom demand have been reported. No restoration date has been given.

A first incident a week earlier

This is not the first outage this month. On October 21, several FPS Finance sites, including finances.belgium.be, finimmoweb.be and ruling.be, had already been taken offline as a preventive measure after the disclosure of critical PHP vulnerabilities, Cyberattaque.org reports. MyMinfin had remained accessible at the time. According to FPS Finance, most sites were back online by October 22. Cyberattaque.org says no link has been established between that episode and the current attack. In France, the government took the same precaution: it shut down the prefecture websites before the PHP patch.

Taxpayers: extended deadline and caution with fake messages

The administration promises a "sufficient" extension to taxpayers whose return was due on October 31. The new date will be announced "as soon as possible." There is therefore no need to look for another way to file urgently.

The main immediate risk lies elsewhere. A highly publicized outage often serves as a pretext for scammers. Expect emails or text messages mentioning "restoration of your account," "tax regularization" or a "new filing procedure." FPS Finance had already warned on September 30 about phishing campaigns impersonating it. For any information, use official channels and type the site address yourself.

Two questions remain open: the nature of the attack and the date MyMinfin will return. FPS Finance has promised further information.

Update of November 13, 2026

The main online services of FPS Finance, Belgium's tax administration, are back. According to the OECCBB, a Belgian organization of chartered accountants that relays the administration's announcements, MyMinfin, Tax-on-web and Biztax "are available again and can be used safely." According to FPS Finance, quoted by the same source, the incident was contained within a few hours, the attackers were unable to take control of any application, and "no data was exfiltrated." The administration still has not specified the nature of the attack.

The promised extension runs through November 16 inclusive. According to the Italian daily ItaliaOggi, it applies to returns with special income that were due by October 31. According to the OECCBB, it also covers Biztax deadlines still running on October 28 and several withholding tax returns (September, October and the third quarter of 2026). Payments of the withholding tax on investment income, the payroll withholding tax and various taxes, however, are not postponed: late-payment interest remains due if payment is late.

Not everything is restored. As of November 5, the OECCBB reported that activating, amending or closing a VAT number was still impossible online, as was filing withholding tax on investment income returns. In the meantime, forms 604A, 604B and 604C can be emailed to the relevant FPS Finance office.