Vulnerabilities

MCPJam inspector versions 1.4.2 and earlier are vulnerable to unauthenticated remote code execution (CWE-306): a crafted HTTP request triggers the installation of an MCP server, which results in arbitrary code execution on the host running the inspector. Because the tool binds to 0.0.0.0 by default instead of 127.0.0.1, any machine that can reach the listening port — typically other hosts on the local network, or the internet if port-forwarded — can exploit it with no credentials and no user interaction. A successful attack gives the attacker code execution in the context of the inspector process on developer workstations or servers where the tool is running. Anyone running MCPJam inspector 1.4.2 or earlier is affected, with exposure concentrated among developers working with MCP servers locally. No confirmed in-the-wild exploitation is reported (not in CISA KEV), but a public PoC reference exists and EPSS assigns a 65.8% probability of exploitation within 30 days, making rapid patching advisable.

Do: Upgrade to MCPJam inspector 1.4.3 or later immediately; until patched, bind the tool to 127.0.0.1 or firewall its listening port so only trusted hosts can reach it. Because the flaw requires no authentication, treat any host that ran 1.4.2 or earlier while the port was reachable from untrusted networks as potentially compromised and review for unexpected MCP server installs or process execution.