What’s Vulnerable › Vulnerabilities

CVE-2026-57860: ForgeCode Arbitrary Code Execution via Unvetted .mcp.json in Untrusted Repository

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-17 · updated 2026-10-24
• Weakness: CWE-829

Description

ForgeCode (tailcallhq/forgecode), an AI pair-programming CLI, automatically loads and executes the MCP servers defined in a repository's .mcp.json file on startup without user confirmation. A malicious repository can supply a crafted .mcp.json whose mcpServers entries specify arbitrary command and args values (for example, command: bash with args: ['-c', 'touch /tmp/pwned']). When a user runs the forge CLI inside a cloned untrusted repository, the specified commands are spawned with the invoking user's privileges, resulting in arbitrary code execution. This provides a reliable initial-access and persistence primitive against developers who evaluate untrusted repositories with ForgeCode.

Affected products

• tailcallhq forgecode: all versions

References

• https://github.com/tailcallhq/forgecode
• https://github.com/tailcallhq/forgecode/commit/68ca3a3a26c73c38a700453d3d021b5bbdc15dbd
• https://github.com/tailcallhq/forgecode/issues/3022
• https://github.com/tailcallhq/forgecode/issues/3252
• https://www.vulncheck.com/advisories/forgecode-arbitrary-code-execution-via-unvetted-mcp-json-in-untrusted-repository
• https://github.com/tailcallhq/forgecode/issues/3022

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