CVE-2026-5029 RCE in Code Runner MCP Server
Unauthenticated attackers can execute arbitrary code via the run-code tool when the server is configured with HTTP transport.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-5029?
CVE-2026-5029 is a high-severity code injection vulnerability in Code Runner MCP Server, published on 12 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Weakness: CWE-306
Which versions are affected by CVE-2026-5029?
How do I fix CVE-2026-5029?
No fix has been published for CVE-2026-5029 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-5029 being exploited?
There is no known exploitation of CVE-2026-5029 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-jv4w-6p47-rhcx.