Prototype Pollution in N8n
CVE-2026-77083
n8n is a workflow automation platform. In versions prior to 1.123.69, 2.33.4, and 2.34.1, the JavaScript Code node's VM sandbox did not freeze the sandbox's Function.prototype, allowing an authenticated user with the ability to create and execute workflows to pollute it from within a Code node execution and recover a reference to the host's globalThis, resulting in a sandbox escape. The full exploit chain additionally depends on specific modules being available as allowlisted imports in the deployment's configuration. The issue is fixed in versions 1.123.69, 2.33.4, and 2.34.1.
Vulnerability class: Prototype Pollution
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (28.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001
Affected products
- N8n — versions 2.34.0
- N8n-Io N8n
Weakness classification (CWE)
References
- github.com/n8n-io/n8n/security/advisories/GHSA-c9c6-rq46-h25v (vendor-advisory, Mitigation, Vendor Advisory)
- www.vulncheck.com/advisories/n8n-before-code-node-sandbox-escape-via-function.p… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-77083?
- CVE-2026-77083 is a medium-severity vulnerability in N8n, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 5.9/10. Published 2026-08-20.
- How severe is CVE-2026-77083?
- Medium severity. CVSS v3 base score is 5.9 out of 10.