What is the CVSS score of CVE-2026-21877?

CVE-2026-21877 has a CVSS 3.1 base score of 9.9 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 12.5%.

Is there a public PoC exploit available for CVE-2026-21877?

Yes, a public proof-of-concept exploit is available for CVE-2026-21877. Prioritise patching immediately. EPSS: 12.5%.

How to fix or mitigate CVE-2026-21877?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. Validate that input sanitization is in place for all user-controlled parameters.

N8n CVE-2026-21877

CRITICAL

Code Injection (CWE-94)

2026-01-08 security-advisories@github.com

GHSA-v364-rw7m-3263

RCE Node.js Code Injection N8n

9.9

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Authenticate to n8n instance
Delivery

Access Git node workflow
Exploit

Inject malicious code
Execution

Execute arbitrary code via CWE-94
Impact

Achieve full platform compromise

Vulnerability Assessment

Weakness	CWE CWE-94 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Code injection prevention, sandbox exec MITRE ATT&CK 2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Authenticated user account required on n8n 0.121.2 or below with Git node enabled. Attacker must have permissions to create or modify workflows. Affects self-hosted and n8n Cloud instances.
Impact	CVSS 9.9 (Critical). Low privileges, network vector, low complexity, scope change. EPSS 12.5% – very high exploitation probability. n8n Cloud instances are shared infrastructure, amplifying the blast radius. Patch available.
Exploit ScenarioDerived	An attacker gains basic n8n access (or uses a compromised account), executes code through the Git node or similar mechanism to read the encryption key, then decrypts all stored credentials for connected services (databases, APIs, cloud accounts).

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.

Patch available 12.5% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

n8n workflow automation (through 1.121.2) allows authenticated users to execute arbitrary code via the n8n service, with scope change enabling full compromise of both self-hosted and cloud instances. EPSS 12.5% indicates high exploitation activity. Patch available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 9.9

n8n allows authenticated code execution with scope change, threatening both self-hosted and cloud deployments. High EPSS indicates active exploitation interest.

RemediationAI

Update to n8n 1.121.3 or later immediately. Disable the Git node if not needed. Restrict untrusted user access. Rotate all stored credentials if exploitation is suspected.

Affected Packages

npm n8n fix: 1.121.3

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in npm

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

An authenticated user can exploit code injection (CWE-94) through the n8n workflow engine to execute arbitrary code on the server. The scope change means the attacker can access credentials and connections for all integrated services. This affects both self-hosted and n8n Cloud instances.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 9.9 CRITICAL

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Patch released

Jan 20, 2026 - 15:08 nvd

Patch available

CVE Published

Jan 08, 2026 - 01:15 nvd

CRITICAL 9.9

DescriptionGitHub Advisory

n8n is an open source workflow automation platform. In versions 0.121.2 and below, an authenticated attacker may be able to execute malicious code using the n8n service. This could result in full compromise and can impact both self-hosted and n8n Cloud instances. This issue is fixed in version 1.121.3. Administrators can reduce exposure by disabling the Git node and limiting access for untrusted users, but upgrading to the latest version is recommended.

Executive ViewAI

Why It Matters

Organizations using n8n face critical risk from CVE-2026-21877, a code injection vulnerability rated CVSS 9.9. Successful exploitation could allow attackers to execute arbitrary code or commands on affected systems, potentially leading to full system compromise. With an EPSS score of 12%, exploitation is likely in exposed deployments. A patch is available and should be applied immediately given the critical severity.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Deploy WAF rules to block injection patterns; (2) Restrict network access to affected components; (3) Enable enhanced logging for suspicious activity.

Threat Intelligence Overview

EPSS Score

12.5%

Top 6% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS POC (1)

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC Yes

EPSS 12.5%

Patch available Yes

Active threat Yes

Deciding rule

CRITICAL severity + public POC available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact

Very High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +12

CVSS: +50

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.