Vulnerability · Published May 12, 2026 · Assigned by CERT-PL

CVE-2026-5029RCE in Code Runner MCP Server

High 8.7

In plain English

A high-severity missing authentication in Code Runner MCP Server from Code Runner MCP Server. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.3%top 78.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack tooling1Public PoC

Official description

A remote code execution vulnerability exists in Code Runner MCP Server when run with the --transport http option, which exposes the /mcp JSON-RPC endpoint without authentication on port 3088. An unauthenticated remote attacker can invoke the run-code MCP tool to supply arbitrary source code and execute it via child_process.exec() using the specified language interpreter. This allows execution of arbitrary code with the privileges of the user running the server. This vulnerability has not been fixed and might affect the project in all versions.

Affected products (as reported)

Vendor	Product	Versions
Code Runner MCP Server	Code Runner MCP Server	0 – through *

Weakness: CWE-306 · Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References

https://cert.pl/en/posts/2026/05/CVE-2026-5029 third-party-advisory