Belgium's Tax Portal Goes Dark After Cyberattack, Forcing Government to Push Back Filing Deadline

Belgium has postponed a tax filing deadline after a cyberattack forced its Federal Public Service Finance (FPS Finance) to take its main online tax portal and several related platforms offline. The agency disconnected MyMinfin on 28 October as a precaution while security teams investigated the incident.

FPS Finance extended to 16 November several filing deadlines falling around 31 October. The extension covers specific personal and corporate income-tax returns, Pillar Two filings, DAC6 and country-by-country reports, withholding tax returns and other specified declarations.

It applies to obligations whose deadlines had not expired by 28 October, rather than providing a blanket extension of all Belgian tax deadlines.

FPS Finance said the attack infiltrated its digital environment but was detected within hours, before intruders could take control of applications or access data. Potentially compromised components were isolated. On 29 October, the agency confirmed that no data had been leaked.

Government Takes Tax Platforms Offline as Precaution

FPS Finance said it disconnected MyMinfin and selected online services to prevent possible unauthorised access and isolate the affected infrastructure. The shutdown allows specialist teams to investigate the incident, assess its scope and complete security checks before restoring services. Officials said the affected services must be restored carefully in an isolated environment.

The disruption did not affect the entire agency's digital infrastructure. A large proportion of its other applications and online channels remained available, although some operated with limited functionality.

Despite the initial assurances, authorities have not declared the investigation complete. FPS Finance's statement that there were no indications of compromised data reflects its assessment at the time. Technical investigations remain under way.

Teams are also working to address vulnerabilities and strengthen security before services resume. Officials have not provided further technical details about how the intrusion was detected or stopped.

Tax Filing Deadline Extended to 16 November

The disruption occurred just days before the original 31 October deadline. The extension to 16 November gives affected taxpayers additional time to meet their obligations while MyMinfin and related services remain unavailable. Individuals and companies using the affected platforms will have to monitor official announcements for updates on their restoration.

Taxpayers can keep copies of documents prepared for submission, along with records of access attempts, including timestamps and error messages. Authorities have not identified the attackers, disclosed the origin of the intrusion or provided a precise technical classification.

The incident has also not been linked to two critical vulnerabilities in PHP, a widely used programming language, highlighted in an international security alert earlier in October.

The warnings concerned flaws that could allow remote code execution on web servers. Several European government institutions temporarily took websites offline as a precaution. Belgium's national cybersecurity centre said at the time it had found no evidence of successful exploitation against Belgian websites. That earlier action was preventative. The 28 October shutdown followed a cyberattack against FPS Finance, although officials have not established whether the incidents were connected.

A separate incident affected the US Federal Election Commission (FEC) during the same week. Reuters reported, citing an internal email, that the agency had been targeted in an attempted breach. The FEC confirmed that its electronic filing systems were offline but did not publicly confirm that a hacking attempt caused the disruption.