GHSA-5648-RGJ9-V224: GHSA-5648-RGJ9-V224: Multiple Security Control Bypasses in @zereight/mcp-gitlab

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GHSA-5648-RGJ9-V224: Multiple Security Control Bypasses in @zereight/mcp-gitlab

Vulnerability ID: GHSA-5648-RGJ9-V224
CVSS Score: 8.1
Published: 2026-09-15

A constellation of five distinct security flaws (F1 through F5) in @zereight/mcp-gitlab prior to version 2.1.30 allows unauthenticated remote access, read-only policy bypasses, DNS rebinding, and denial-of-service via session exhaustion.

TL;DR

Multiple critical and high severity flaws in @zereight/mcp-gitlab allow unauthenticated remote access, GraphQL authorization bypasses, and denial of service.

⚠️ Exploit Status: POC

Technical Details

CWE ID: CWE-863
Attack Vector: Network
CVSS: 8.1
Impact: Authorization Bypass & Denial of Service
Exploit Status: Proof-of-Concept
KEV Status: Not Listed

Affected Systems

@zereight/mcp-gitlab
@zereight/mcp-gitlab: < 2.1.30 (Fixed in: 2.1.30)

Code Analysis

Commit: 69e784d

Documentation and changelog update commit finalized

Exploit Details

GitHub Advisory: Includes local validation replication script and details

Mitigation Strategies

Upgrade to version 2.1.30 or later immediately.
Enforce explicit SSE_AUTH_TOKEN when using the SSE server transport.
Configure reverse proxies to enforce robust Origin and Host header verification.
Disable STREAMABLE_HTTP when not strictly required by deployment architectures.

Remediation Steps:

Navigate to your MCP GitLab deployment directory.
Update package dependency via npm: npm install @zereight/mcp-gitlab@2.1.30 or edit package.json.
Restart the service and confirm the version corresponds to 2.1.30 or above.
Validate headers by sending invalid host queries and verifying a 403 response.

References

Read the full report for GHSA-5648-RGJ9-V224 on our website for more details including interactive diagrams and full exploit analysis.

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