n8n — CVE-2026-25049: New Sandbox Escape Bypass Enables Full Server Takeover

  • CVE-2026-25049 (CVSS 9.4) is a critical expression-sandbox escape in n8n, the open-source workflow automation platform widely used to orchestrate AI agents, RAG pipelines, and LLM tool chains.
  • The flaw is a bypass of the December 2025 fix for CVE-2025-68613 (CVSS 9.9). Researcher Fatih Çelik, who reported the original bug, describes both as "the same vulnerability — the second is just a bypass for the initial fix."
  • Root cause: A mismatch between TypeScript compile-time type system and JavaScript runtime behavior allows crafted expressions using destructuring syntax to escape the sandbox. Attackers can then call process.binding('spawn_sync') to execute arbitrary OS commands, sidestepping module restrictions.
  • Attack path: An authenticated user creates a workflow with a publicly accessible webhook (no auth). A single line of JS in a node expression is enough to trigger full RCE. Once the workflow is activated, anyone on the internet can hit the webhook and run commands.
  • Impact confirmed by Pillar Security: Full read of environment variables including N8N_ENCRYPTION_KEY, decryption of every stored credential, filesystem access, lateral movement to connected cloud accounts, and hijack of downstream AI workflows.
  • Affects n8n versions prior to 1.123.17 and 2.5.2. n8n Cloud was patched; the primary risk is self-hosted instances.
  • At least 10 independent researchers (Endor Labs, Pillar Security, SecureLayer7, and others) discovered and reported variants, indicating the attack surface was broadly accessible.
  • Public exploit details and PoCs are now available, increasing urgency.

Why it matters

  • n8n is a central hub for AI agent orchestration — it typically stores API keys for LLM providers, vector databases, SaaS tools, and cloud accounts. Compromising n8n means compromising the entire AI pipeline.
  • The webhook-to-RCE chain turns any internet-facing n8n instance into a one-click server takeover — no special tooling required.
  • This is the second critical sandbox escape in n8n in under three months (after CVE-2025-68613 in December and CVE-2026-1470 / CVE-2026-0863 in January), signaling that expression sandboxing in workflow engines remains a fragile security boundary.

What to do

  • Upgrade immediately to n8n ≥ 1.123.17 or ≥ 2.5.2.
  • Audit webhooks: Identify any workflows with public, unauthenticated webhooks and disable or restrict them until patched.
  • Rotate all stored credentials: Assume the N8N_ENCRYPTION_KEY and every credential stored in n8n may have been exposed if the instance was internet-reachable.
  • Restrict workflow creation: Treat the ability to create or edit workflows as a privileged operation — not a default for every team member.
  • Network isolation: Place n8n behind a VPN or zero-trust proxy; never expose it directly to the internet.

Sources