Critical n8n Flaws Exposed: Sandbox Escape Vulnerabilities Allow Complete Server Takeover

A series of critical vulnerabilities in the popular n8n workflow automation platform has sent shockwaves through the cybersecurity community, with researchers revealing that any authenticated user can escape the platform’s sandbox environment and gain complete control over the host server.

The “Ni8mare” Continues: CVE-2026-25049 Details

The vulnerabilities, collectively tracked as CVE-2026-25049, affect all versions of n8n prior to 2.5.2 and 1.123.17. What makes this particularly alarming is the low barrier to exploitation—any user with basic workflow creation or editing permissions can weaponize these flaws to execute arbitrary code on the server.

According to cybersecurity firm Pillar Security, the attack requires “nothing special. If you can create a workflow, you can own the server.” This stark assessment underscores the severity of what researchers are calling a “complete takeover” scenario.

The Technical Breakdown: How Attackers Can Escape the Sandbox

The vulnerabilities stem from n8n’s inadequate sanitization mechanism, which fails to properly sandbox user-written JavaScript expressions in workflows. Researchers discovered that while TypeScript typings suggest certain security checks are in place, these controls are not enforced at runtime—creating a dangerous type-confusion vulnerability.

Pillar Security’s researchers demonstrated that exploiting CVE-2026-25049 enables attackers to:

• Execute arbitrary system commands on the n8n server
• Steal all stored credentials and secrets (API keys, OAuth tokens)
• Access sensitive configuration files
• Compromise the filesystem and internal systems
• Pivot to connected cloud accounts
• Hijack AI workflows (intercept prompts, modify responses, redirect traffic)

In multi-tenant environments, the implications are even more severe, as attackers could potentially pivot to access other tenants’ data by reaching internal cluster services.

The Attack Chain: From Workflow to Full Compromise

The full attack chain, as illustrated by Pillar Security, demonstrates how attackers can leverage seemingly innocuous workflow creation capabilities to achieve complete server control. The process involves:

1. Creating or modifying a workflow with malicious JavaScript expressions
2. Bypassing n8n’s weak sandboxing through type confusion vulnerabilities
3. Escaping to the Node.js global object
4. Achieving remote code execution (RCE)
5. Gaining complete server control

Researchers at Endor Labs independently discovered similar sanitization bypasses and provided a proof-of-concept exploit that achieves RCE in affected versions. Their analysis revealed that the sanitization function incorrectly assumes keys in property accesses are strings in attacker-controlled code, despite this not being enforced at runtime.

The Discovery Timeline: A Patch That Wasn’t Enough

The story of CVE-2026-25049 is one of incomplete fixes and persistent vulnerabilities. Pillar Security initially reported their findings to n8n on December 21, 2025, demonstrating a chained bypass that allowed sandbox escape and RCE. n8n implemented a fix on December 23, but upon further analysis, Pillar found the patch incomplete.

A second escape mechanism remained possible through different operations achieving equivalent results. n8n developers confirmed this bypass on December 30, leading to the eventual release of version 2.4.0 on January 12, 2026, which properly addressed the issue.

SecureLayer7 researchers, who discovered the vulnerability while analyzing the previous CVE-2025-68613 flaw, reported that it took more than 150 failed attempts to refine a successful bypass. Their detailed technical report explains how they achieved “server-side JavaScript execution using the Function constructor.”

Real-World Impact: GreyNoise Reports Suspicious Activity

While no public reports of CVE-2026-25049 exploitation have emerged yet, cybersecurity firm GreyNoise reported seeing potentially malicious activity targeting exposed n8n endpoints vulnerable to the related “Ni8mare” flaw (CVE-2026-21858). Between January 27 and February 3, they logged at least 33,000 requests probing these endpoints.

Although this activity could be research-related, the probing for the /proc filesystem indicates clear interest in post-exploitation capabilities—suggesting that cybercriminals are actively scanning for vulnerable n8n installations.

Urgent Action Required: Update Now

n8n users must update immediately to version 1.123.17 or 2.5.2. For those unable to update immediately, n8n has provided temporary mitigation steps:

• Limit workflow creation and editing permissions to fully trusted users only
• Deploy n8n in a hardened environment with restricted OS privileges and network access
• Reduce the impact of potential exploitation through network segmentation

Pillar Security additionally recommends rotating the N8N_ENCRYPTION_KEY and all credentials stored on the server, as well as reviewing workflows for suspicious expressions that might indicate prior compromise.

The Bigger Picture: Growing Popularity Attracts Attackers

The emergence of these critical vulnerabilities highlights the double-edged sword of n8n’s growing popularity. As more organizations adopt workflow automation platforms, they become increasingly attractive targets for cybercriminals seeking to compromise enterprise systems.

The combination of CVE-2026-25049 with the previously disclosed Ni8mare flaw (CVE-2026-21858) creates a particularly dangerous situation where attackers have multiple paths to compromise n8n installations, potentially affecting hundreds of thousands of enterprise AI systems that rely on the platform.

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