Ninja Forms WordPress: a critical vulnerability exploited by hackers

WordPress sites using the Ninja Forms plugin are under constant threat of cyberattacks. Hackers are looking to exploit a critical flaw, thus threatening thousands of sites worldwide. Discover the details of this vulnerability and the measures to take to protect your site.

Key points to remember

• Hackers launch about 3,600 intrusion attempts per day by exploiting a vulnerability in Ninja Forms.
• The flaw allows the execution of malicious PHP scripts without prior authentication, endangering approximately 90,000 installations.
• A patch is available, but many sites remain unprotected due to update delays.

Details of the security flaw

A design error in the Ninja Forms plugin, specifically in the File Upload module, was identified by researcher Sélim Lanouar. The vulnerability exploits the CVE-2026-0740 repository, allowing attackers to inject web shells and steal sensitive data without requiring authentication.

Hackers take advantage of this flaw to modify upload settings and force file writing into critical server directories. By using special character sequences, they can reach the root directory, further compromising the security of attacked sites.

Consequences for site administrators

Administrators are encouraged to immediately install version 3.3.27 of Ninja Forms to mitigate the risk. However, the slowness of updates in some installations allows hackers to exploit the flaw. Cybersecurity experts, like those at Wordfence, urge enhanced monitoring of access logs to detect any suspicious activity.

Companies investing in premium plugins hope for enhanced security, but this proprietary model often limits independent code review. Unlike the WordPress core, these add-ons do not benefit from continuous community vigilance, which can leave doors open to cybercriminals.

Recommendations for effective protection

Limiting the number of third-party modules can reduce the potential attack surface. Site managers must remain vigilant in the face of increasing malicious requests targeting their contact forms. Even with hosts blocking thousands of suspicious connections every hour, hackers persist in finding new vulnerable targets.

Experts also recommend keeping a technological watch on official patches, as hackers often analyze these updates to identify weaknesses in outdated versions.

Cybersecurity and monitoring of WordPress websites

In 2026, website security remains a major priority for administrators. Implementing proactive measures such as continuous monitoring, regular plugin updates, and using robust security solutions is essential to protect online data and infrastructures. Vigilance and education in cybersecurity are key to countering the persistent threats posed by cybercriminals.

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