CVE-2026-73533 in Ninja Tables Pro Plugin
Summary
by MITRE • 08/13/2026
Ninja Tables Pro 5.2.11 contains an embedded malicious code vulnerability introduced via a tampered plugin build served through a decommissioned update server. The tampered build introduced a rogue PHP file (app/Library/updater/NinjaTableDataSync.php) that established a backdoor REST API endpoint, dropped persistent PHP files in mu-plugins and uploads directories, installed a passwordless administrator account, and registered scheduled tasks that survived plugin removal.
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Analysis
by VulDB Data Team • 08/13/2026
The vulnerability in Ninja Tables Pro version 5.2.11 represents a sophisticated supply chain attack that demonstrates the critical risks associated with compromised software distribution channels. This malicious code injection occurred through a tampered plugin build that was distributed via a decommissioned update server, exploiting the trust model that users place in legitimate software repositories. The attack vector highlights the importance of maintaining secure software development practices and proper integrity verification mechanisms. The compromised build introduced a backdoor that operates at the core level of WordPress installations, making it particularly dangerous due to its persistence across system updates and plugin removals.
The technical implementation of this vulnerability involves multiple malicious components that work in concert to establish persistent unauthorized access. The rogue PHP file located at app/Library/updater/NinjaTableDataSync.php serves as the primary backdoor mechanism, creating a REST API endpoint that allows remote attackers to execute arbitrary commands on affected systems. This endpoint operates with elevated privileges and can be accessed without authentication, making it particularly dangerous for administrators who may not realize their systems have been compromised. The malicious code also demonstrates sophisticated persistence mechanisms by dropping additional PHP files into both the mu-plugins directory and uploads folder, ensuring that the backdoor remains operational even if the primary plugin is removed or updated.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as the malicious code establishes a passwordless administrator account that can perform any action within the WordPress environment. This accounts for the complete compromise of affected installations, potentially allowing attackers to modify content, steal sensitive data, install additional malware, or use compromised systems for further attacks. The registration of scheduled tasks that survive plugin removal represents a particularly insidious aspect of this attack, as it ensures that malicious activity continues even after administrators attempt to clean up their systems. These persistent tasks can trigger automated actions at regular intervals, making detection more difficult and allowing attackers to maintain long-term access without requiring repeated compromise attempts.
The vulnerability aligns with several common attack patterns documented in the attack framework, including techniques for maintaining persistence through scheduled tasks and credential manipulation. From a cybersecurity perspective, this represents a critical flaw that violates fundamental security principles of least privilege and integrity verification. The attack demonstrates how attackers can exploit the trust placed in legitimate software updates to introduce sophisticated backdoors that are difficult to detect and remove completely. Organizations should consider implementing comprehensive monitoring for unusual REST API activity and scheduled task execution patterns as part of their defense strategy against similar supply chain attacks.
Security practitioners should recognize this vulnerability as a prime example of why organizations must implement robust software integrity verification processes, including digital signature validation and checksum verification before installing any third-party plugins or themes. The incident underscores the importance of maintaining updated security monitoring systems that can detect anomalous behavior patterns such as unexpected file creation in critical directories or unauthorized administrative account creation. Additionally, implementing network-based detection measures to identify communication with known malicious endpoints and establishing incident response procedures for rapid containment and remediation are essential defensive measures against this type of supply chain attack.
This vulnerability represents a significant risk to WordPress installations that rely on third-party plugins for functionality, demonstrating how a single compromised component can lead to complete system compromise. The attack pattern observed here is consistent with supply chain attacks that have affected major software vendors in recent years, emphasizing the need for organizations to maintain vigilance against malicious updates and to implement layered security controls. The persistence mechanisms employed by this backdoor make it particularly challenging to eliminate completely, requiring thorough system analysis and potentially complete reinstallation of affected environments to ensure complete remediation.
The broader implications of this vulnerability extend to the entire WordPress ecosystem, as it demonstrates how attackers can leverage legitimate update mechanisms to deploy malicious code across numerous installations simultaneously. This type of attack can significantly impact organizations that depend on WordPress for their web presence, potentially affecting customer data, business operations, and regulatory compliance requirements. Security professionals should consider implementing automated patch management processes with integrity verification, maintaining up-to-date threat intelligence feeds, and establishing robust backup and recovery procedures to mitigate the impact of similar supply chain attacks in the future. The incident also highlights the critical importance of vendor security practices and the need for regular security audits of third-party software components that are integrated into organizational systems.
The vulnerability's classification aligns with common weakness enumerations including CWE-502 for deserialization of untrusted data and CWE-78 for command injection, while also demonstrating characteristics consistent with attack techniques documented in the MITRE ATT&CK framework under persistence and privilege escalation categories. Organizations must understand that this type of attack requires not only technical remediation but also organizational changes in how software supply chains are managed and verified. The backdoor's ability to survive plugin removal indicates a sophisticated approach to maintaining access that reflects advanced attacker capabilities typically associated with nation-state or highly organized threat groups rather than casual attackers. This vulnerability serves as a stark reminder of the evolving sophistication of cyber threats targeting web application platforms and the critical need for continuous security awareness and proactive defense measures across all system components.