CVE-2026-65591: n8n Legacy Expression Evaluator Sanitizer Bypass Vulnerability

HIGH
Advisory Identifier: GHSA-pm35-fqvh-cq5g
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CWE-917
Published
Advisory Summary

CVE-2026-65591 is a HIGH legacy expression evaluator sanitizer bypass vulnerability (CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')) affecting n8n libraries in the npm ecosystem. The issue involves legacy expression evaluator sanitizer bypass leads to authenticated code execution. Remediation is available by upgrading affected packages to version 1.123.64, 2.30.1, 2.29.8.

CVE-2026-65591 at a Glance

CVE Identifier CVE-2026-65591
GHSA Identifier GHSA-pm35-fqvh-cq5g
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
Affected Product n8n
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-65591

To remediate this vulnerability, upgrade all affected n8n dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

n8n fixed: 1.123.64 
npm install n8n@1.123.64
n8n fixed: 2.30.1 
npm install n8n@2.30.1
n8n fixed: 2.29.8 
npm install n8n@2.29.8
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls n8n

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-65591, inspect your project dependencies using npm:

npm ls n8n

Analyze the terminal output to locate any version of n8n in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.123.64), your application is affected.

Note: The npm ls n8n command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection'), where the product constructs all or part of an expression language (el) statement in a framework such as a java server page (jsp) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended el statement before it is executed. In n8n, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Impact The legacy expression evaluator's computed-member sanitizer can be bypassed by an authenticated user with workflow create or modify permissions. Successful exploitation grants the attacker host-level code execution as the n8n process. The legacy expression engine is the default engine in affected versions. ## Patches The issue has been fixed in n8n versions 1.123.64, 2.29.8, and 2.30.1. Users should upgrade to one of these versions or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict n8n instance access to fully trusted users only. - Switch to the non-legacy expression engine by setting `N8N_EXPRESSION_ENGINE=vm`. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.

CVE-2026-65591 Affected n8n Versions

3 component(s)
Fixed Versions:
1.123.642.30.12.29.8
Product / Package Ecosystem Affected Versions Fixed Version
n8n
npm/n8n
npm
< 1.123.64
1.123.64
n8n
npm/n8n
npm
≥ 2.30.0
< 2.30.1
2.30.1
n8n
npm/n8n
npm
≥ 2.0.0-rc.0
< 2.29.8
2.29.8

References

GitHub Advisory / Wiki ADVISORY
https://github.com/n8n-io/n8n/security/advisories/GHSA-pm35-fqvh-cq5g
NVD — CVE-2026-65591 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-65591
n8n Source Repository REPOSITORY
https://github.com/n8n-io/n8n
n8n Release RELEASE
https://github.com/n8n-io/n8n/releases/tag/n8n@1.123.64
n8n Release RELEASE
https://github.com/n8n-io/n8n/releases/tag/n8n@2.29.8
n8n Release RELEASE
https://github.com/n8n-io/n8n/releases/tag/n8n@2.30.1
www.vulncheck.com/advisories/n8n-befo... WEB
https://www.vulncheck.com/advisories/n8n-before-sanitizer-bypass-remote-code-execution

Frequently Asked Questions

What is CVE-2026-65591?
CVE-2026-65591 is a security vulnerability in n8n involving Legacy Expression Evaluator Sanitizer Bypass Leads to Authenticated Code Execution under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection').
Which n8n versions are affected?
Affected versions include releases prior to 1.123.64, 2.30.1, 2.29.8 across affected packages: n8n.
What version fixes CVE-2026-65591?
Upgrading to 1.123.64, 2.30.1, 2.29.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is n8n affected?
Yes, n8n is affected in releases prior to 1.123.64, 2.30.1, 2.29.8. Upgrade your dependency to 1.123.64, 2.30.1, 2.29.8 or later.
What CWE is associated with CVE-2026-65591?
CVE-2026-65591 is classified under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') (The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.).
How can I check npm dependencies for CVE-2026-65591?
Run the dependency tree command: 'npm ls n8n'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-pm35-fqvh-cq5g",
  "modified" : "2026-07-22T22:02:04Z",
  "published" : "2026-07-22T22:02:04Z",
  "aliases" : [ "CVE-2026-65591" ],
  "summary" : "n8n: Legacy Expression Evaluator Sanitizer Bypass Leads to Authenticated Code Execution",
  "details" : "## Impact\nThe legacy expression evaluator's computed-member sanitizer can be bypassed by an authenticated user with workflow create or modify permissions. Successful exploitation grants the attacker host-level code execution as the n8n process.\n\nThe legacy expression engine is the default engine in affected versions.\n\n## Patches\nThe issue has been fixed in n8n versions 1.123.64, 2.29.8, and 2.30.1. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Restrict n8n instance access to fully trusted users only.\n- Switch to the non-legacy expression engine by setting `N8N_EXPRESSION_ENGINE=vm`.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "n8n"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.123.64"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "n8n"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.30.0"
      }, {
        "fixed" : "2.30.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "n8n"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0-rc.0"
      }, {
        "fixed" : "2.29.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/security/advisories/GHSA-pm35-fqvh-cq5g"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-65591"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/n8n-io/n8n"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/releases/tag/n8n@1.123.64"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/releases/tag/n8n@2.29.8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/n8n-io/n8n/releases/tag/n8n@2.30.1"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/n8n-before-sanitizer-bypass-remote-code-execution"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-917" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-22T22:02:04Z",
    "nvd_published_at" : null
  }
}