CVE-2026-47751Network attack vector

Runner code execution via untrusted MCP configuration

Published Jul 16, 2026 · Updated Jul 16, 2026

Command injection in Anthropic Claude Code Action before 1.0.74 allows remote authenticated users to execute code on GitHub Actions runners. The action checks out a pull request's head, reads its .mcp.json through default setting sources, and enables every project MCP server before permission gating. A repository must use the action on pull requests, and a privileged user or automatic trigger must invoke it; successful execution can expose workflow secrets.

CVSS severity5.3
Medium
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Anthropic Claude Code Action before 1.0.74 allows remote authenticated users to execute code on GitHub Actions runners. The action checks out a pull request's head, reads its .mcp.json through default setting sources, and enables every project MCP server before permission gating. A repository must use the action on pull requests, and a privileged user or automatic trigger must invoke it; successful execution can expose workflow secrets.

The record

CVE
CVE-2026-47751
Published
Jul 16, 2026
Updated
Jul 16, 2026
Vendor
Anthropic
Product
Claude Code Action
Classifications
CWE-78, CWE-200, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.0.74

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Anthropic · Claude Code Actionversion=< 1.0.74

Published CVSS scores

5.3GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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