Medium 5.3Published Jul 16, 2026

CVE-2026-47751Claude Code Action: Malicious MCP Server Configuration in PRs Enables Remote Code Execution and Secret Exfiltration

Updated under an hour ago (Oct 26, 2026, 11:50 PM ET)

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It affects anthropics claude-code-action. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for anthropics claude-code-action

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-78, CWE-200
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Jul 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

anthropics claude-code-action anthropics:claude_code_action (from the name)	before 1.0.74	CNA record

References

References

https://github.com/anthropics/claude-code-action/security/advisories/GHSA-8q5r-mmjf-575q	x-refsource-confirm
https://github.com/anthropics/claude-code-action/pull/1066	x-refsource-misc
https://github.com/anthropics/claude-code-action/commit/9ddce40de8c1ab71fb6303a125fdad0968dc1312	x-refsource-misc
https://github.com/anthropics/claude-code-action/releases/tag/v1.0.74	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.