Companies and governments around the world raced on Thursday to patch critical vulnerabilities in the widely used PHP programming language, as millions of hacking attempts were reported and authorities across Asia activated emergency cybersecurity measures.

The rush came after government websites in Europe and elsewhere went offline on Wednesday, with the disclosure of the flaws sending website operators scrambling to protect their systems.

PHP developers released urgent security fixes on Wednesday after vulnerabilities that had remained in the software for years were uncovered using artificial intelligence. The developers urged all users to update immediately.

Cloudflare Chief Executive Matthew Prince said attempts to exploit the vulnerabilities had surged dramatically following their public disclosure.

“In the 10 hours before it was publicly announced, across the network we saw thousands of attempts to exploit it,” Prince said in a post on social media platform X late on Wednesday.

“That jumped to tens of thousands in the 45 minutes post announcement, hundreds of thousands within 2 hours, and millions now.”

The vulnerabilities could allow attackers to execute malicious commands without authentication, steal sensitive information or take websites offline, according to South Korea’s science ministry.

Asian governments activate emergency measures

South Korea raised its private-sector cybersecurity alert level on Thursday and activated emergency response measures, citing the increased risk of hacking attacks.

The presidential National Security Office convened an emergency meeting involving intelligence, defence and science ministry officials to coordinate responses across the public, private and military sectors.

The science ministry said it had issued security guidance to approximately 28,000 companies with registered chief information security officers and 5,900 members of a government information-sharing network.

Operators of critical infrastructure, web-hosting companies and data centres were also alerted.

Authorities urged organisations to install the latest PHP security updates and introduce temporary safeguards where immediate patching was not possible.

China’s industry ministry similarly called on organisations and users to inspect their systems immediately and upgrade to the latest secure version of PHP.

It also recommended strengthening cybersecurity monitoring and promptly changing accounts, passwords and security keys.

Japanese banks and government services affected

In Japan, Mitsubishi UFJ Financial Group said on Thursday it was temporarily suspending some internet services as part of emergency security measures.

Japan’s Finance Ministry also suspended some website content and online services while implementing protective measures.

Prime Minister Sanae Takaichi urged website operators on Wednesday to check whether their systems used PHP and prepare to install the security fixes.

The disruptions and emergency measures highlight the potential impact of vulnerabilities in PHP, a programming language widely used to power websites and online services.

The disclosure of the flaws, followed by the rapid escalation in attempted exploitation, has prompted governments and businesses to accelerate security updates to protect their systems from possible attacks.