Summary
n8n: External Secrets Permission Bypass via Expression Parser Mismatch
Workarounds
If upgrading is not immediately possible, administrators should consider the following temporary mitigations:
- Restrict credential creation and update permissions to fully trusted users only.
- Audit existing credentials for unexpected external secret references.
These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
Impact
Due to a mismatch between the static validation check and the runtime expression engine, an authenticated user with credential create or update permissions, but without the externalSecret:list scope, could embed external secret references into credentials in forms the validation did not detect. These references would resolve at workflow execution time, exposing secret values the user was not authorized to access.
This issue only affects instances where an external secrets provider is configured and Advanced Permissions are in use.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
The issue has been fixed in n8n versions 1.123.61, 2.27.4, and 2.28.1. Users should upgrade to one of these versions or later to remediate the vulnerability.
Frequently Asked Questions
- What is CVE-2026-59259? CVE-2026-59259 is a medium-severity security vulnerability in n8n (npm), affecting versions < 1.123.61. It is fixed in 1.123.61, 2.28.1, 2.27.4.
- Which versions of n8n are affected by CVE-2026-59259? n8n (npm) versions < 1.123.61 is affected.
- Is there a fix for CVE-2026-59259? Yes. CVE-2026-59259 is fixed in 1.123.61, 2.28.1, 2.27.4. Upgrade to this version or later.
- Is CVE-2026-59259 exploitable, and should I be worried? Whether CVE-2026-59259 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-59259 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-59259?
- Upgrade
n8nto 1.123.61 or later - Upgrade
n8nto 2.28.1 or later - Upgrade
n8nto 2.27.4 or later
- Upgrade