VTA-004557 – n8n Sandbox Breach Exposes Enterprise AI Systems to Complete Takeover

CVE-2026-25049 represents a critical remote code execution (RCE) vulnerability in n8n, a popular open-source workflow automation platform used for integrating services like APIs, databases and apps. What sets this apart from typical sandbox escapes is its exploitation of JavaScript’s destructuring syntax (const {constructor} = () => {})which slips past n8n’s multi-layered defenses including regex pattern blocking, AST sanitization and runtime property checks that target common access methods like dot or bracket notation.

n8n’s expression system lets users write dynamic JavaScript for data manipulation within workflows, but it evaluates these in a sandboxed environment to prevent abuse. The flaw emerges because the sanitizers assume property access follows familiar patterns, overlooking destructuring’s unique AST structure (ObjectPattern nodes instead of MemberExpression). Combined with arrow functions’ lexical ‘this’ binding, attackers bypass all five security layers, regex for “.constructor”, AST checks, runtime validators, function binding and property removal using a compact payload like ( ={{(() => { const {constructor} = ()=>{}; return constructor(‘return process.env’)(); })()}} ). This grants access to process.env or even process.binding() for command spawning, distinguishing it from prototype pollution or type confusion tactics by chaining multiple overlooked syntax quirks into full RCE.

The threat escalates dramatically with n8n’s webhook feature, attackers craft a public, unauthenticated webhook workflow embedding the payload, exposing it internet-wide for remote triggering via simple HTTP POSTs. Impacts include credential theft from n8n’s vault, database exfiltration, backdoor installation and pivoting to connected systems, far beyond info disclosure in similar vulns. Patched via runtime type checks and expanded sanitization in 2.5.2, it underscores why static types and partial parsers fail against JavaScript’s flexibility; runtime validation and allowlists are essential.

Severity:
High

Attack Surface:
Supply Chain (Third-party vendors), System Management Service, Web Application

Tactics:
Command and Control, Credential Access, Discovery, Execution, Lateral Movement, Persistence, Privilege Escalation

Techniques:
T1059 – Command and Scripting Interpreter
T1190 – Exploitation of Public-Facing Application
T1203 – Exploitation for Client Execution
T1078 – Valid Accounts
T1543 – Create or Modify System Process

Indicator of Compromise:
https://otx.alienvault.com/pulse/6983f56f34239acc4d858100

References:
1. https://www.endorlabs.com/learn/cve-2026-25049-n8n-rce
2. https://blog.securelayer7.net/cve-2026-25049/

SuperPRO’s Threat Countermeasures Procedures:
1. Upgrade n8n to version 1.75.0 or later (or the latest stable release that patches CVE-2026-25049).
2. If upgrading immediately is not possible, disable execution of custom JavaScript or expressions in workflows.
3. Restrict n8n service execution to a non-root, least-privileged system account.
4. Block external access to n8n admin interfaces using firewall rules or reverse proxy IP allowlists.
5. Rotate all credentials stored in n8n workflows, including API keys, tokens and service passwords.
6. Monitor for suspicious child processes spawned by the n8n service (e.g., /bin/bash, cmd.exe, powershell).
7. Deploy application-level sandboxing (e.g., Docker seccomp / AppArmor profiles) to limit OS command execution.

Contributed by: Thivya