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CVE-2026-61560 critical CVSS 9.8

Path Traversal in @zereight/mcp-gitlab (CVE-2026-61560)

Summary

Path traversal in @zereight/mcp-gitlab (CVE-2026-61560). Successful exploitation can lead to full system takeover. Exploitable via POST /projects/. Mitigation: upgrade to 2.1.27 or later.

Original description

The description as published by the source.

Summary

The SSE transport mode (SSE=true) exposes all MCP tools without any authentication. The upload_markdown tool reads arbitrary files from the server's local filesystem via an unsanitized file_path parameter and uploads them to a GitLab project. Combined, any unauthenticated network-reachable attacker can read /proc/self/environ to steal the server's GITLAB_PERSONAL_ACCESS_TOKEN and achieve full GitLab account takeover. This is the default configuration for Docker deployments.

Details

Two issues chain together:

1. No authentication on SSE transport (src/index.ts:7350-7388)

When SSE=true (the intended mode for Docker deployments per docker-compose.yaml), the /sse and /messages endpoints have zero authentication middleware. Any HTTP client that can reach the port can establish a session and invoke all ~100+ tools using the server's configured PAT.

// src/index.ts:7354 — no auth check
app.get("/sse", async (_: Request, res: Response) => {
    const serverInstance = createServer();
    const transport = new SSEServerTransport("/messages", res);
    await serverInstance.connect(transport);
});

Remote Authorization (REMOTE_AUTHORIZATION=true) is explicitly incompatible with SSE mode (src/index.ts:1833-1839), so there is no way to add per-request auth in this transport.

2. Arbitrary file read in upload_markdown (src/index.ts:5461-5503)

The upload_markdown tool calls fs.readFileSync(filePath) where `fileP…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-61560 has been found in @zereight/mcp-gitlab.
Attackers can target a specific entry point like POST /projects/ over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: upgrade @zereight/mcp-gitlab to 2.1.27 or later.
If unsure, ask your IT team or search "@zereight/mcp-gitlab CVE-2026-61560" on the vendor's site.

CVE-2026-61560 (@zereight/mcp-gitlab) — CWE-22 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /projects/ / upload_markdown / file_path / GITLAB_PERSONAL_ACCESS_TOKEN
Patched: 2.1.27 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

Path traversal (CWE-22) exists in @zereight/mcp-gitlab. Attackers reach the vulnerable code path via POST /projects/ without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of @zereight/mcp-gitlab. Attack surface: POST /projects/ / upload_markdown / file_path / GITLAB_PERSONAL_ACCESS_TOKEN.

🔥 Severity

Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 2.1.27.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual POST /projects/ requests with malformed payloads or SQL meta-characters. Run grep -r '@zereight/mcp-gitlab' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r '@zereight/mcp-gitlab' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で @zereight/mcp-gitlab を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'POST /projects/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /projects/ への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch 
    Upgrade @zereight/mcp-gitlab to 2.1.27

    ステージング環境で 2.1.27 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify 
    Replay attack against POST /projects/ on staging to confirm patch closes the vector

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

npm @zereight/mcp-gitlab
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.27"}]}]

References

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