CVE-2026-47751
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| anthropics | claude-code-action | < 1.0.74 | affected |
Weaknesses
- CWE-78: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
- CWE-200: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
References
- https://github.com/anthropics/claude-code-action/security/advisories/GHSA-8q5r-mmjf-575q
- https://github.com/anthropics/claude-code-action/pull/1066
- https://github.com/anthropics/claude-code-action/commit/9ddce40de8c1ab71fb6303a125fdad0968dc1312
- https://github.com/anthropics/claude-code-action/releases/tag/v1.0.74
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