CVE-2026-55413: ToolJet - Marketplace Plugin Poisoning Enables Instance-Wide Remote Code Execution

Synopsis

This is a marketplace plugin poisoning vulnerability in ToolJet, an open-source platform for building internal tools and workflows. Any authenticated user holding a builder role (the free-tier role) can overwrite a globally shared marketplace plugin with arbitrary JavaScript, which then executes server-side with full Node.js privileges (including access to require and process) whenever any other user on the instance triggers a query using that plugin. Successful exploitation gives an attacker remote code execution across the entire ToolJet deployment and effectively poisons the plugin supply chain instance-wide. No fix version has been published yet; HarborGuard is tracking the advisory for patch availability.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the ToolJet service over the network to submit the malicious plugin payload via the web interface.

• AuthenticationRequired

  A low-privilege builder-role account is sufficient; no administrative credentials are needed.

• Victim interactionNot required

  No victim interaction is needed; the malicious code executes automatically the next time any user on the instance triggers a query using the poisoned plugin.

• Attack complexityDetail

  The exploit is reliable and condition-free; no race conditions, memory layout dependencies, or environmental setup are required.

Blast Radius

• Executes arbitrary JavaScript server-side with full Node.js access, giving the attacker read and write access to the underlying filesystem and environment variables including secrets.
• Modifies a globally shared marketplace plugin, meaning every user and workflow on the entire ToolJet instance is exposed to the malicious code on their next query execution.
• Enables exfiltration of database credentials, API keys, and any other secrets accessible to the ToolJet server process.
• Allows the attacker to pivot laterally from the ToolJet host to other services reachable from within the deployment network.