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CVE-2026-65594 n8n-io CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-22T12:18:19.527Z and has not been modified since then. The vulnerability affects n8n workflow automation tool, especially those with MCP Server Trigger workflows configured with n8n OAuth2 authentication. User and project isolation can be broken, allowing an attacker to execute workflows in the owner's project context with the owner's stored credentials.

Vendor
n8n-io
Product
n8n
CVSS
MEDIUM 5.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-22
Original CVE updated
2026-07-27
Advisory published
2026-07-22
Advisory updated
2026-07-27

Who should care

Users of n8n workflow automation tool, especially those with MCP Server Trigger workflows configured with n8n OAuth2 authentication, should verify their instances and apply patches to prevent unauthorized access. This includes reviewing workflow configurations, monitoring user activities, and implementing additional access controls.

Technical summary

n8n versions before 2.29.8 and 2.30.x before 2.30.1 are vulnerable to an authorization bypass. An attacker can register an OAuth client, self-approve consent for another user's workflow, and obtain a valid token, allowing them to execute the workflow in the owner's project context with the owner's stored credentials. This can lead to unauthorized access to sensitive data and potential lateral movement.

Defensive priority

Medium priority for n8n users, especially those with active MCP Server Trigger workflows and OAuth2 authentication.

Recommended defensive actions

  • Verify n8n instance version and apply patches to 2.29.8 or 2.30.1
  • Review and restrict OAuth client registrations
  • Monitor workflow executions and user activities
  • Implement additional access controls and logging
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability was introduced in n8n version 2.27.0 with the OAuth 2.1 consent and token-issuance flow. Official patches are available in versions 2.29.8 and 2.30.1. Evidence limits suggest that defenders verify instances with at least one active MCP Server Trigger workflow configured with n8n OAuth2 authentication. Defensive verification tasks include reviewing workflow configurations, monitoring user activities, and implementing additional access controls.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-65594 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-65594

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-65594 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-65594

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.