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N8nApplication

CVE-2026-0863

CRITICAL · 9.9 CVSS v3.1 Published 2026-01-18
Fix available
A fix is available. Upgrade to after 2.4.2 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Using string formatting and exception handling, an attacker may bypass n8n's python-task-executor sandbox restrictions and run arbitrary unrestricted Python code in the underlying operating system. The vulnerability can be exploited via the Code block by an authenticated user with basic permissions and can lead to a full n8n instance takeover on instances operating under "Internal" execution mode. If the instance is operating under the "External" execution mode (ex. n8n's official Docker image) - arbitrary code execution occurs inside a Sidecar container and not the main node, which significantly reduces the vulnerability impact.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

n8n's python-task-executor sandbox can be bypassed through string formatting and exception handling, allowing authenticated users with basic permissions to execute arbitrary Python code. In 'Internal' execution mode, this leads to full OS-level code execution on the main n8n instance, while 'External' mode limits impact to a Sidecar container.

MitigationImplement proper sanitization of string formatting and exception handling in the python-task-executor sandbox, or ensure instances run in 'External' execution mode to isolate code execution.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
N8nApplication
Affected:<= 1.123.14>= 2.0.0, <= 2.3.5>= 2.4.0, <= 2.4.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check n8n version
    Run `n8n --version` or check the version through the UI (Settings > About) and compare it against the affected ranges: <= 1.123.14, 2.0.0 to 2.3.5, or 2.4.0 to 2.4.2
    Affected if Your installed version falls within any of the affected ranges listed
  2. Identify if python-task-executor is in use
    Review your n8n workflows to see if any nodes use the Python Task Executor functionality, or check the system logs for python-task-executor activity
    Affected if python-task-executor is actively used in your workflows or enabled in the configuration
  3. Check execution mode configuration
    Inspect the n8n configuration files or environment variables for the `EXECUTIONS_MODE` setting, or check the UI under Settings > Executions > Execution Mode
    Affected if The execution mode is set to 'Internal' rather than 'External'
  4. Verify authenticated user access
    Review user permissions and roles in n8n (Settings > Users) to determine if users with basic or standard permissions exist who could access the python-task-executor
    Affected if Basic or standard user accounts exist with access to workflow execution capabilities
  5. Inspect sandbox configuration
    Check the python-task-executor settings or configuration for any sandbox-related parameters that control string formatting and exception handling behavior
    Affected if Custom sandbox settings exist or default sandbox configuration is in use without additional hardening

You are affected if your n8n version is within the vulnerable ranges AND python-task-executor is enabled AND you are using Internal execution mode with users who have basic permissions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 2.4.2
Vendor patch github.com →
Interim mitigation

Implement proper sanitization of string formatting and exception handling in the python-task-executor sandbox, or ensure instances run in 'External' execution mode to isolate code execution.

Recommended fix Moderate confidence

n8n 1.123.15+ (for v1.x) or n8n 2.3.6+ (for v2.0-2.3.x) or n8n 2.4.3+ (for v2.4.x)

  1. 1. Identify the current n8n version running in your environment using the UI (Settings > About) or CLI
  2. 2. For n8n version 1.x: Upgrade to version 1.123.15 or later
  3. 3. For n8n version 2.0.x - 2.3.x: Upgrade to version 2.3.6 or later
  4. 4. For n8n version 2.4.x: Upgrade to version 2.4.3 or later
  5. 5. After upgrade, verify the python-task-executor sandbox is functioning correctly by testing Code block executions
  6. 6. Review execution logs to confirm the sandbox is properly restricting Python code execution
Caveat Review n8n release notes between your current version and target version for any breaking changes in workflow compatibility or API behavior

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in N8n Scoped from the published advisory
  • Consultation3.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
24.0 hours of engineering $4,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-0863 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data