CVE-2026-56777

Description

n8n before 2.25.7 and 2.26.x before 2.26.2 contains an abstract syntax tree (AST) security validator bypass in the Python Code node. An authenticated user with permission to create or modify workflows containing a Python Code node can bypass the validator and access the task executor module namespace. The issue only affects self-hosted instances where the Python Task Runner is enabled; where N8N_BLOCK_RUNNER_ENV_ACCESS is configured to allow it, this can disclose environment variables accessible to the task runner process.

CVSS v3.1 Score

5.0

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0025

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-184 CWE-184

Affected Products

Vendor	Product	Versions
n8n	n8n	< 2.25.7
n8n	n8n	2.26.0 — 2.26.2

References

Advisories & Patches

https://github.com/n8n-io/n8n/security/advisories/GHSA-jwm3-qcfw-c5pp

Other References

https://www.vulncheck.com/advisories/n8n-ast-validator-bypass-in-python-code-node

Frequently Asked Questions

What is CVE-2026-56777? +

n8n before 2.25.7 and 2.26.x before 2.26.2 contains an abstract syntax tree (AST) security validator bypass in the Python Code node. An authenticated user with permission to create or modify workflows containing a Python Code node can bypass the validator and access the task executor module namespace. The issue only affects self-hosted instances where the Python Task Runner is enabled; where N8N_BLOCK_RUNNER_ENV_ACCESS is configured to allow it, this can disclose environment variables accessible to the task runner process. It has a CVSS v3.1 base score of 5.0 (MEDIUM).

How severe is CVE-2026-56777? +

CVE-2026-56777 has a CVSS v3.1 score of 5.0 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0025, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-56777? +

CVE-2026-56777 affects products from n8n, specifically: n8n. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-56777? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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