# CVE-2026-61559

## Summary

- **CVE ID:** CVE-2026-61559
- **Severity:** CRITICAL
- **CVSS Score:** 9.6 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N)
- **CWE:** CWE-918
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 17, 2026

## Description

`@zereight/mcp-gitlab` is a Model Context Protocol server for GitLab. Starting in version 0.0.1 and prior to version 2.1.27, when the environment variable `ENABLE_DYNAMIC_API_URL=true` is set, the server reads the `X-GitLab-API-URL` HTTP request header and uses it as the base URL for all outbound GitLab API calls made within that request. The server validates that the value is a well-formed URL (`new URL(dynamicApiUrl)`) but applies no allowlist or hostname restriction. The server then attaches the victim's `Private-Token` to every outbound fetch that uses the redirected URL. Any caller who can reach the HTTP transport can set `X-GitLab-API-URL` to an attacker-controlled host. The next GitLab API call the server makes delivers the victim's token to that host. Version 2.1.27 contains a patch.

## Affected Products

- zereight — gitlab-mcp (>= 0.0.1, < 2.1.27)

## References

- [CNA](https://github.com/zereight/gitlab-mcp/security/advisories/GHSA-2h44-8472-frjj)
- [CNA](https://github.com/zereight/gitlab-mcp/pull/625)
- [CNA](https://github.com/zereight/gitlab-mcp/commit/6ffb4cc70706fd05b1ab80901676bc2998b6db6d)
- [CNA](https://github.com/zereight/gitlab-mcp/releases/tag/v2.1.27)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 19.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._