CVE-2026-61559 @zereight/mcp-gitlab Vulnerable to Server-Side Request Forgery
Attackers can redirect API calls to malicious hosts via a header, stealing victim tokens when dynamic API URL is enabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61559?
CVE-2026-61559 is a critical server-side request forgery vulnerability in zereight gitlab-mcp, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-61559?
2 open source packages ship an affected version, including @zereight/mcp-gitlab.
| Package | Affected | Fixed in |
|---|---|---|
@zereight/mcp-gitlab npm | From 0.0.1 | 2.1.27 |
@zereight/mcp-gitlab npm | From 0.0.1 | 2.1.27 |
How do I fix CVE-2026-61559?
Upgrade @zereight/mcp-gitlab to 2.1.27 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-61559 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61559 exists.
Sources
Also known as GHSA-2h44-8472-frjj.