CVE-2026-23744 is a critical-severity (CVSS 9.8) Missing Authentication vulnerability in @mcpjam/inspector. 7 public exploit references exist, 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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-23744 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
MCPJam inspector is the local-first development platform for MCP servers. 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. 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. Version 1.4.3 contains a patch.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @mcpjam/inspector | all versions | 1.4.3npm install @mcpjam/inspector@1.4.3 |
Research 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
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-23744 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-23744. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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?
O3 Security finds CVE-2026-23744 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.