CVE-2026-47751

Claude Code Action: Malicious MCP Server Configuration in PRs Enables Remote Code Execution and Secret Exfiltration

Published: Jul 16, 2026Updated: Jul 18, 2026 Sources: CVE List NVDCWE-78

N/ACVSS

NVD MITRE

Description

Claude Code Action is a general-purpose GitHub action that runs Claude Code on GitHub pull requests and issues. Prior to 1.0.74, because the action checked out attacker-controlled pull request head branches, read .mcp.json from the working directory via default setting sources, and unconditionally enabled all project MCP servers via enableAllProjectMcpServers, an attacker who opened a pull request containing a malicious .mcp.json file could achieve arbitrary code execution on the GitHub Actions runner and exfiltrate secrets available to the workflow (such as API keys and tokens) when a privileged user or an automatic trigger invoked the Claude action on the pull request. This issue is fixed in version 1.0.74, which restores .claude/ and .mcp.json from the pull request base branch before the CLI runs.

No summary for this CVE yet.

Weaknesses

CWE-78 CWE-200

Affected Products

anthropics

commercial·USaka anthropic-sdk-python, anthropic-sdk-typescript, claude-code

claude-code-actionSaaS

AI / ML / llm-serving-inference

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Collection

Execution

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References

https://github.com/anthropics/claude-code-action/commit/9ddce40de8c1ab71fb6303a125fdad0968dc1312

github.com

https://github.com/anthropics/claude-code-action/pull/1066

github.com

https://github.com/anthropics/claude-code-action/releases/tag/v1.0.74

github.com

and 1 more references View all →

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