{"affected":[{"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-8q5r-mmjf-575q/GHSA-8q5r-mmjf-575q.json"},"package":{"ecosystem":"GitHub Actions","name":"anthropics/claude-code-action"},"ranges":[{"events":[{"introduced":"0"},{"fixed":"1.0.74"}],"type":"ECOSYSTEM"}]}],"aliases":["CVE-2026-47751"],"database_specific":{"cwe_ids":["CWE-200","CWE-78"],"github_reviewed":true,"github_reviewed_at":"2026-06-10T19:33:48Z","nvd_published_at":"2026-07-16T17:16:57Z","severity":"MODERATE"},"details":"Due to the combination of checking out PR head branches (attacker-controlled), reading `.mcp.json` from the working directory via default setting sources, and unconditionally enabling all project MCP servers via `enableAllProjectMcpServers`, it was possible for an attacker who opened a PR containing a malicious `.mcp.json` file to achieve arbitrary code execution on the GitHub Actions runner. This could lead to exfiltration of secrets available to the workflow (such as API keys and tokens) when a privileged user triggered the Claude action on the PR. Exploiting this required the ability to open a pull request against a repository using the claude-code-action and a privileged user or automatic trigger to invoke the action on that PR.\n\nUsers pinned to a vulnerable version of claude-code-action are advised to update to the latest version. Users referencing anthropics/claude-code-action@v1, anthropics/claude-code-action@beta, anthropics/claude-code-action@main, or other non-pinned tags will have received this fix already\n\nClaude Code thanks hackerone.com/reptou for reporting this issue.","id":"GHSA-8q5r-mmjf-575q","modified":"2026-09-15T05:30:04.987810812Z","published":"2026-06-10T19:33:48Z","references":[{"type":"WEB","url":"https://github.com/anthropics/claude-code-action/security/advisories/GHSA-8q5r-mmjf-575q"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47751"},{"type":"WEB","url":"https://github.com/anthropics/claude-code-action/pull/1066"},{"type":"WEB","url":"https://github.com/anthropics/claude-code-action/commit/9ddce40de8c1ab71fb6303a125fdad0968dc1312"},{"type":"PACKAGE","url":"https://github.com/anthropics/claude-code-action"},{"type":"WEB","url":"https://github.com/anthropics/claude-code-action/releases/tag/v1.0.74"}],"schema_version":"1.9.0","severity":[{"score":"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","type":"CVSS_V4"}],"summary":"Claude Code Action: Malicious MCP Server Configuration in PRs Enables Remote Code Execution and Secret Exfiltration"}