CVE-2026-86083: n8n: Expression Sandbox Escape via Shared Builtin Tampering and Code-Printer Injection Leads to Code Execution

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-08 · updated 2026-09-11
Weakness: CWE-94

Description

n8n is an open source workflow automation platform. Prior to 1.123.76, 2.37.7, and 2.38.2, the legacy expression engine generated source text by calling the mutable global JSON.stringify while printing synthetic string literals and interpolating timezone data. An expression could replace JSON.stringify and cause later generated source to contain executable attacker-controlled code. The affected code-generation paths include packages/@n8n/expression-runtime/src/bridge/isolated-vm-bridge.ts and packages/@n8n/tournament/src/ExpressionBuilder.ts, and the issue does not affect the vm expression engine. This issue is fixed in versions 1.123.76, 2.37.7 and 2.38.2.

Affected products

n8n-io n8n: before 1.123.76; from 2.0.0 before 2.37.7; from 2.38.0 before 2.38.2 — fixed in 1.123.76, 2.37.7, 2.38.2

How to fix

Upgrade to a fixed version: n8n-io n8n 1.123.76, 2.37.7, 2.38.2. Check the vendor advisory for mitigations.

References

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