CVE-2026-53818: OpenClaw MCP loopback auth bypass

Q: Is CVE-2026-53818 actively exploited?

No confirmed active exploitation of CVE-2026-53818 has been reported, but organizations should still patch proactively.

Q: How to fix CVE-2026-53818?

1. Patch immediately: upgrade OpenClaw to 2026.4.24 or later (see GHSA-rj6p-xmxr-qj4h for patch details). 2. If patching is blocked, disable the MCP loopback feature in OpenClaw configuration or restrict loopback path access to owner-equivalent process contexts only. 3. Enumerate all owner-only tool definitions to assess the blast radius if the bypass has already been exploited. 4. Review OpenClaw access and audit logs for unexpected invocations of owner-only tools from non-owner process contexts. 5. Apply least-privilege to OpenClaw service accounts and restrict local access to systems where OpenClaw runs.

Q: What systems are affected by CVE-2026-53818?

This vulnerability affects the following AI/ML architecture patterns: agent frameworks, MCP-based tool ecosystems, multi-user AI agent deployments, agentic automation pipelines.

Q: What is the CVSS score for CVE-2026-53818?

CVE-2026-53818 has a CVSS v3.1 base score of 6.6 (MEDIUM). The EPSS exploitation probability is 0.10%.

CISO Take

OpenClaw before 2026.4.24 has a missing authorization check (CWE-862) in its MCP loopback feature, allowing any low-privileged local user to invoke owner-only tools and skip before-tool-call security hooks without restriction. The High integrity impact is operationally significant: with AC:L, PR:L, and no user interaction required, anyone with a local shell on a shared OpenClaw deployment can bypass the authorization layer that owner-only policies were explicitly designed to enforce — collapsing the trust boundary between agent privilege tiers. While CISA KEV status is negative and no public exploit exists today, OpenClaw's track record of 155 CVEs in this package indicates systemic security debt that elevates the probability of further abuse. Upgrade to 2026.4.24 immediately per GHSA-rj6p-xmxr-qj4h; if patching is blocked, disable the MCP loopback feature and audit logs for unexpected owner-only tool invocations.

Sources: NVD GitHub Advisory ATLAS vulncheck.com

What is the risk?

Medium CVSS (6.6) with a local attack vector limits direct internet-facing exposure, but the High integrity impact combined with trivial exploitation prerequisites (AC:L, PR:L, UI:N) makes this reliably exploitable in any shared or multi-user OpenClaw deployment. In AI agent contexts where owner-only tools gate sensitive operations — file writes, credential-bearing API calls, privileged data access — bypassing these controls effectively nullifies the primary authorization control. The package's history of 155 CVEs indicates systemic authorization debt, raising confidence that this loopback bypass reflects a broader pattern rather than an isolated defect.

How does the attack unfold?

Local Access

Attacker obtains low-privilege local access to a system running OpenClaw with the MCP loopback feature enabled.

AML.T0012

Tool Discovery

Attacker enumerates available owner-only tools and before-tool-call hooks to identify high-value restricted operations to target via the loopback path.

AML.T0084.001

Authorization Bypass

Attacker routes tool invocation requests through the MCP loopback path, bypassing both owner-only policy enforcement and before-tool-call hook execution.

AML.T0107

Privileged Tool Execution

Restricted owner-only tools execute with elevated effective permissions, enabling data exfiltration, agent configuration tampering, or lateral movement via connected services.

AML.T0053

Local Access

Attacker obtains low-privilege local access to a system running OpenClaw with the MCP loopback feature enabled.

AML.T0012

Tool Discovery

Attacker enumerates available owner-only tools and before-tool-call hooks to identify high-value restricted operations to target via the loopback path.

AML.T0084.001

Authorization Bypass

Attacker routes tool invocation requests through the MCP loopback path, bypassing both owner-only policy enforcement and before-tool-call hook execution.

AML.T0107

Privileged Tool Execution

Restricted owner-only tools execute with elevated effective permissions, enabling data exfiltration, agent configuration tampering, or lateral movement via connected services.

AML.T0053

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
OpenClaw	pip	—	No patch
4 dependents 37% patched ~3d to patch Full package profile →
OpenClaw	npm	< 2026.4.24	`2026.4.24`
4 dependents 37% patched ~3d to patch Full package profile →

How severe is it?

CVSS 3.1

6.6 / 10

EPSS

0.1%

chance of exploitation in 30 days

Higher than 1% of all CVEs

Source: EPSS v3 — FIRST.org

Exploitation Status

No known exploitation

Sophistication

Trivial

What is the attack surface?

AV Local

AC Low

PR Low

UI None

S Unchanged

C Low

I High

A Low

What should I do?

5 steps

Patch immediately: upgrade OpenClaw to 2026.4.24 or later (see GHSA-rj6p-xmxr-qj4h for patch details).
If patching is blocked, disable the MCP loopback feature in OpenClaw configuration or restrict loopback path access to owner-equivalent process contexts only.
Enumerate all owner-only tool definitions to assess the blast radius if the bypass has already been exploited.
Review OpenClaw access and audit logs for unexpected invocations of owner-only tools from non-owner process contexts.
Apply least-privilege to OpenClaw service accounts and restrict local access to systems where OpenClaw runs.

What does CISA's SSVC say?

Decision Track

Exploitation none

Automatable No

Technical Impact partial

Source: CISA Vulnrichment (SSVC v2.0). Decision based on the CISA Coordinator decision tree.

How is it classified?

Auth Bypass Code Execution Data Extraction Agent Plugin Framework AML.T0053 - AI Agent Tool Invocation AML.T0084.001 - Tool Definitions AML.T0107 - Exploitation for Defense Evasion AML.T0112.000 - Local AI Agent

Which compliance frameworks are affected?

This CVE is relevant to:

EU AI Act

Article 15 - Accuracy, robustness and cybersecurity

ISO 42001

A.6.2 - AI system access control and authorization Clause 8.4 - AI system operational controls

NIST AI RMF

GOVERN 6.1 - Policies and procedures for AI risk management GOVERN 6.2 - Organizational risk management policies for AI

OWASP LLM Top 10

LLM07 - Insecure Plugin Design

Frequently Asked Questions

What is CVE-2026-53818?

OpenClaw before 2026.4.24 has a missing authorization check (CWE-862) in its MCP loopback feature, allowing any low-privileged local user to invoke owner-only tools and skip before-tool-call security hooks without restriction. The High integrity impact is operationally significant: with AC:L, PR:L, and no user interaction required, anyone with a local shell on a shared OpenClaw deployment can bypass the authorization layer that owner-only policies were explicitly designed to enforce — collapsing the trust boundary between agent privilege tiers. While CISA KEV status is negative and no public exploit exists today, OpenClaw's track record of 155 CVEs in this package indicates systemic security debt that elevates the probability of further abuse. Upgrade to 2026.4.24 immediately per GHSA-rj6p-xmxr-qj4h; if patching is blocked, disable the MCP loopback feature and audit logs for unexpected owner-only tool invocations.

Is CVE-2026-53818 actively exploited?

No confirmed active exploitation of CVE-2026-53818 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-53818?

1. Patch immediately: upgrade OpenClaw to 2026.4.24 or later (see GHSA-rj6p-xmxr-qj4h for patch details). 2. If patching is blocked, disable the MCP loopback feature in OpenClaw configuration or restrict loopback path access to owner-equivalent process contexts only. 3. Enumerate all owner-only tool definitions to assess the blast radius if the bypass has already been exploited. 4. Review OpenClaw access and audit logs for unexpected invocations of owner-only tools from non-owner process contexts. 5. Apply least-privilege to OpenClaw service accounts and restrict local access to systems where OpenClaw runs.

What systems are affected by CVE-2026-53818?

This vulnerability affects the following AI/ML architecture patterns: agent frameworks, MCP-based tool ecosystems, multi-user AI agent deployments, agentic automation pipelines.

What is the CVSS score for CVE-2026-53818?

CVE-2026-53818 has a CVSS v3.1 base score of 6.6 (MEDIUM). The EPSS exploitation probability is 0.10%.

What is the AI security impact?

Affected AI Architectures

agent frameworksMCP-based tool ecosystemsmulti-user AI agent deploymentsagentic automation pipelines

MITRE ATLAS Techniques

AML.T0053 AI Agent Tool Invocation

AML.T0084.001 Tool Definitions

AML.T0107 Exploitation for Defense Evasion

AML.T0112.000 Local AI Agent

Compliance Controls Affected

EU AI Act: Article 15

ISO 42001: A.6.2, Clause 8.4

NIST AI RMF: GOVERN 6.1, GOVERN 6.2

OWASP LLM Top 10: LLM07

What are the technical details?

Original Advisory

OpenClaw before 2026.4.24 contains an authorization bypass vulnerability in the MCP loopback feature that allows non-owner callers to skip owner-only tool policies and before-tool-call hooks. Attackers can invoke owner-only behavior through the affected loopback path to execute restricted tools when the feature is enabled and reachable.

Exploitation Scenario

A low-privileged local user on a shared AI workstation or server running OpenClaw identifies the MCP loopback endpoint — documented in OpenClaw's own architecture documentation. Using a minimal script or direct API call, they route a tool invocation request through the loopback path, which lacks the authorization check enforcing owner-only restrictions. The before-tool-call hook — intended to validate permissions prior to execution — is also bypassed on this code path. The attacker executes a restricted tool such as a file-write, a credential-retrieving API call, or an agent configuration modification without elevated OS credentials, potentially exfiltrating sensitive data or pivoting to connected systems via the invoked tool's capabilities.

Weaknesses (CWE)

CWE-862 Missing Authorization Primary CWE-862 Missing Authorization Primary CWE-862 Missing Authorization

CWE-862 — Missing Authorization: The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

[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.