CVE-2026-23744: REC in MCPJam inspector due to HTTP Endpoint exposes

Should you act?

High exploit likelihood

EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 67.5%, percentile 99: FIRST’s model estimates a 67.5% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes @mcpjam/inspector (npm) <= 1.4.2, fixed in 1.4.3. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

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.

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

Weakness type: CWE-306.

Product: @mcpjam/inspector (npm) · Assigned by: GitHub_M · Published: 2026-01-16

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 67.52% probability of exploitation activity in the next 30 days; percentile 99.

Timeline

• 2026-01-16 — CVE record last updated
• 2026-01-16 — CVE record published by GitHub_M
• 2026-01-16 — GitHub-reviewed advisory GHSA-232v-j27c-5pp6 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-232v-j27c-5pp6 github.com
2. CVE.org record CVE-2026-23744 cve.org
3. NVD entry CVE-2026-23744 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

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