CVE-2026-9803

A flaw was found in Keycloak's ClientRegistrationAuth component. A remote unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with a malformed 'Authorization: Bearer' header to any client registration endpoint. This can lead to an...

PT-2026-44196

Name of the Vulnerable Software and Affected Versions Keycloak affected versions not specified Description A flaw in the ClientRegistrationAuth component allows a remote unauthenticated attacker to cause a Denial of Service DoS. By sending a specially crafted POST request with a malformed...

Keycloak 缓冲区错误漏洞

Keycloak is an open-source identity and access management solution developed by Keycloak. Keycloak has a buffer error vulnerability, which originates from the ClientRegistrationAuth component. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST...

A First Measurement Study on Authentication Security in Real-World Remote MCP Servers

The Model Context Protocol MCP is emerging as a common interface connecting large language models LLMs with external services. Remote deployments are becoming increasingly important as agents connect to user-linked online services, such as social, productivity, and financial services. In such...

Server-side Request Forgery (SSRF)

Overview Affected versions of this package are vulnerable to Server-side Request Forgery SSRF via unvalidated URL processing in the OAuth2 dynamic client registration process. An attacker can access internal network resources or sensitive information by supplying malicious URLs to be fetched by t...

Spring AI MCP Security: Unvalidated URL Fetching (SSRF)

Summary The mcp-security framework fails to implement the mandatory SSRF mitigations outlined in the Model Context Protocol MCP security specifications. Specifically, it processes untrusted URLs for OAuth-related discovery and metadata without verifying if the targets are malicious or internal to...

GHSA-QJP4-4JVR-XQG3 Spring AI MCP Security: Unvalidated URL Fetching (SSRF)

Summary The mcp-security framework fails to implement the mandatory SSRF mitigations outlined in the Model Context Protocol MCP security specifications. Specifically, it processes untrusted URLs for OAuth-related discovery and metadata without verifying if the targets are malicious or internal to...

PT-2026-41691

Name of the Vulnerable Software and Affected Versions mcp-security versions prior to 0.1.9 Description The mcp-security framework fails to implement mandatory Server-Side Request Forgery SSRF mitigations—a flaw where an attacker can induce the server to make requests to an unintended location—as...

CVE-2026-42236

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memor...

CVE-2026-42236 n8n: Unauthenticated Denial of Service via MCP Client Registration

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memor...

CVE-2026-42236 n8n: Unauthenticated Denial of Service via MCP Client Registration

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memor...

EUVD-2026-27111

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memor...

CVE-2026-42236

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memor...

CVE-2026-42236

Summary: CVE-2026-42236 affects n8n, an open source workflow automation platform. The issue is in the MCP OAuth client registration endpoint, which accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could perform a denia...

CVE-2026-42236 n8n: Unauthenticated Denial of Service via MCP Client Registration

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memor...

n8n 安全漏洞

n8n is an open-source, scalable workflow automation tool developed by n8n. Versions of n8n prior to 1.123.32, 2.17.4, and 2.18.1 contained security vulnerabilities. These vulnerabilities stemmed from the MCP OAuth client registration endpoint accepting unauthenticated requests without proper...

Cross-site Scripting (XSS)

Overview n8n-editor-ui is a Workflow Editor UI for n8n Affected versions of this package are vulnerable to Cross-site Scripting XSS via the clientname parameter in the MCP OAuth client registration process. An attacker can execute arbitrary JavaScript in a victim's authenticated browser session b...

Allocation of Resources Without Limits or Throttling

Overview n8n is a n8n Workflow Automation Tool Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the MCP OAuth client registration process. An attacker can exhaust server memory resources and render the instance unavailable by sending lar...

GHSA-49M9-PGWW-9VQ6 n8n Vulnerable to Unauthenticated Denial of Service via MCP Client Registration

Impact The MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memory resources by sending large registration payloads, rendering the n8n instance unavailable. T...

Improper Input Validation

org.springframework.security:spring-security-oauth2-authorization-server is vulnerable to Improper Input Validation. The vulnerability is due to insufficient validation of client metadata fields during dynamic client registration, which allows an attacker to register a malicious client and exploi...