CVE-2026-118640: n8n Chat Hub authz bypass lets

CISO Take

n8n's Chat Hub fails to enforce authorization on tool registration, so a user holding only the low-privilege global:chatUser role can add restricted tool types and run them through chat. Those tools can execute sandboxed code, read permitted files, and invoke instance workflows, Data Tables, and agents that the role was never meant to reach. Exposure is limited by the medium rating (CVSS 5.4), the need for a valid low-privilege account, and the absence of KEV listing, a public exploit, a Nuclei template, or an EPSS score. The practical risk is higher than the score suggests, because agent and workflow platforms often hold connected credentials and business data, and many deployments give chat access to broad internal audiences. Upgrade to n8n 1.123.85, 2.43.5, or 2.44.1 or later, and review who holds the chatUser role in the meantime.

Sources:NVDGitHub AdvisoryATLASvulncheck.com

What is the risk?

Medium overall. Exploitation is network-reachable with low complexity, low privileges, and no user interaction (CVSS 5.4, C:L/I:L/A:N). There is no KEV listing, no public exploit, no Nuclei template, and no EPSS data, so exploitation likelihood looks low today. Environmental risk rises where chat users are numerous or semi-trusted and where workflows, Data Tables, or agents connect to sensitive systems. The CWE-863 flaw makes it a privilege escalation within the platform.

How does the attack unfold?

Initial Access

Attacker authenticates to n8n with a low-privilege global:chatUser account.

AML.T0012

Privilege Escalation

Attacker registers restricted tool types in Chat Hub, bypassing the missing authorization check (CWE-863).

AML.T0053

Execution

Attacker runs the tools through chat to execute sandboxed code and invoke instance workflows and agents.

AML.T0053

Impact

Attacker reads permitted files and Data Tables and triggers workflows using connected credentials.

AML.T0085.001

Initial Access

Attacker authenticates to n8n with a low-privilege global:chatUser account.

AML.T0012

Privilege Escalation

Attacker registers restricted tool types in Chat Hub, bypassing the missing authorization check (CWE-863).

AML.T0053

Execution

Attacker runs the tools through chat to execute sandboxed code and invoke instance workflows and agents.

AML.T0053

Impact

Attacker reads permitted files and Data Tables and triggers workflows using connected credentials.

AML.T0085.001

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
n8n	npm	—	No patch
208.5KOpenSSF 7.116 dependentsPushed 7d ago44% patched~19d to patchFull package profile →

Do you use n8n? You're affected.

How severe is it?

CVSS 3.1

5.4 / 10

EPSS

0.2%

chance of exploitation in 30 days

Higher than 9% of all CVEs

Source: EPSS v3 — FIRST.org

Exploitation Status

No known exploitation

Sophistication

Trivial

What is the attack surface?

AVNetwork

ACLow

PRLow

UINone

SUnchanged

CLow

ILow

ANone

What should I do?

1 step

1) Upgrade n8n to 1.123.85, 2.43.5, 2.44.1 or later, depending on your release line. 2) Until patched, restrict the global:chatUser role to trusted users or disable Chat Hub access for untrusted accounts. 3) Audit which workflows, Data Tables, and agents are exposed to chat and remove unnecessary exposure. 4) Apply least privilege to credentials used by those workflows. 5) Review execution logs and Chat Hub activity for tool registrations or code-execution runs started by chatUser accounts. 6) Keep the instance off the public internet or behind SSO and network controls.

How is it classified?

Auth BypassCode ExecutionAgentPluginFrameworkAML.T0012- Valid Accounts AML.T0053- AI Agent Tool Invocation AML.T0085.001- AI Agent Tools

Which compliance frameworks are affected?

This CVE is relevant to:

EU AI Act

Article 15-Accuracy, robustness and cybersecurity

ISO 42001

A.6.2.6-AI system operation and monitoring

NIST AI RMF

MANAGE 2.3-Responses to AI risks are prioritized and managed

OWASP LLM Top 10

LLM06-Excessive Agency

Frequently Asked Questions

What is CVE-2026-118640?

n8n's Chat Hub fails to enforce authorization on tool registration, so a user holding only the low-privilege global:chatUser role can add restricted tool types and run them through chat. Those tools can execute sandboxed code, read permitted files, and invoke instance workflows, Data Tables, and agents that the role was never meant to reach. Exposure is limited by the medium rating (CVSS 5.4), the need for a valid low-privilege account, and the absence of KEV listing, a public exploit, a Nuclei template, or an EPSS score. The practical risk is higher than the score suggests, because agent and workflow platforms often hold connected credentials and business data, and many deployments give chat access to broad internal audiences. Upgrade to n8n 1.123.85, 2.43.5, or 2.44.1 or later, and review who holds the chatUser role in the meantime.

Is CVE-2026-118640 actively exploited?

No confirmed active exploitation of CVE-2026-118640 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-118640?

1) Upgrade n8n to 1.123.85, 2.43.5, 2.44.1 or later, depending on your release line. 2) Until patched, restrict the global:chatUser role to trusted users or disable Chat Hub access for untrusted accounts. 3) Audit which workflows, Data Tables, and agents are exposed to chat and remove unnecessary exposure. 4) Apply least privilege to credentials used by those workflows. 5) Review execution logs and Chat Hub activity for tool registrations or code-execution runs started by chatUser accounts. 6) Keep the instance off the public internet or behind SSO and network controls.

What systems are affected by CVE-2026-118640?

This vulnerability affects the following AI/ML architecture patterns: agent frameworks, workflow automation platforms, LLM chat interfaces, multi-user AI agent deployments.

What is the CVSS score for CVE-2026-118640?

CVE-2026-118640 has a CVSS v3.1 base score of 5.4 (MEDIUM). The EPSS exploitation probability is 0.19%.

What is the AI security impact?

Affected AI Architectures

agent frameworksworkflow automation platformsLLM chat interfacesmulti-user AI agent deployments

MITRE ATLAS Techniques

AML.T0012Valid Accounts

AML.T0053AI Agent Tool Invocation

AML.T0085.001AI Agent Tools

Compliance Controls Affected

EU AI Act: Article 15

ISO 42001: A.6.2.6

NIST AI RMF: MANAGE 2.3

OWASP LLM Top 10: LLM06

What are the technical details?

Original Advisory

n8n before 1.123.85, 2.43.5, and 2.44.1 contains an authorization bypass vulnerability in Chat Hub that allows chat-only users to register restricted tool types. Users with the global:chatUser role can add and run tools through chat to execute sandboxed code, access permitted files, and use instance workflows, Data Tables, and agents.

Exploitation Scenario

An attacker with a legitimate chatUser account, such as an employee, contractor, or a phished or self-registered user, opens Chat Hub and registers a restricted tool type that the role should not be able to add. They use chat to run sandboxed code and call internal workflows and agents. Through those, they read data from Data Tables and files they are permitted to access, and trigger workflows that use privileged connected credentials. This yields data exposure and unauthorized actions without ever touching the admin interface.

Weaknesses (CWE)

CWE-863Incorrect AuthorizationPrimary CWE-863Incorrect Authorization

CWE-863 — Incorrect Authorization: The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

[Architecture and Design] Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
[Architecture and Design] Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].

Source: MITRE CWE corpus.