CVE-2026-5029

HIGH

RCE in Code Runner MCP Server

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References
Third Party Advisory third-party-advisory
https://cert.pl/en/posts/2026/05/CVE-2026-5029

Scores

CVSS v4 8.7
EPSS 0.0029
EPSS Percentile 20.5%
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-306
Status published
Products (1)
Code Runner MCP Server/Code Runner MCP Server
Published May 12, 2026
Tracked Since May 12, 2026