ZITADEL Actions V1 Sandbox Escape & Host File Read via require() [CVE-2026-89027]

Summary of ZITADEL Actions V1 Sandbox Escape Vulnerability Vulnerability Overview Vulnerability Name: Actions V1 sandbox escape: host file read via require() Vulnerability Type: Sandbox Escape / Arbitrary File Read Severity: High (CVSS 8.7/10) CVE ID: CVE-2026-89027 CWE: CWE-284 (Improper Access Control) Description: ZITADEL Actions V1 allows organization Action authors to read files on the ZITADEL host file system using the module loader. In common self-hosted deployments, this vulnerability can be exploited to steal bootstrap credentials (including the Login Client PAT) and escalate privileges from a single-tenant organization owner to an instance administrator. Affected Scope Affected Versions: - 4.x: 4.0.0 - 4.16.0 (including RC versions) - 3.x: 3.0.0 - 3.4.12 (including RC versions) Impact Scenarios: - Able to read host files that are accessible to the process, including configurations or keys mounted into the API container - In deployments following the ZITADEL documented bootstrap path, instance-level credentials (such as and ) can be recovered - Able to access any file readable by (including those with and permissions) Scope Note: This vulnerability affects Actions V1. No host command execution has been identified. The impact depends on what the ZITADEL process can read on the disk and the deployment layout. Remediation Patched Versions: - 4.x: Upgrade to 4.16.1 - 3.x: Upgrade to 3.4.13 Fix Details: The patch disables module loading based on the host file system within Action scripts, only allowing loading from modules. Temporary Mitigations (Workarounds) If an immediate upgrade is not possible: 1. Restrict users who can create, update, or attach Actions—do not grant / (or ) permissions to untrusted multi-tenant environment administrators 2. Audit file system paths in existing Actions 3. Remove or rotate bootstrap credential files (login-client-pat, machine key) to make them unreadable from the API process file system 4. Limit the host file system exposure of the ZITADEL process (no unnecessary readable keys outside of binaries) Code/Exploit Snippets in the Page The page does not include complete POC code blocks, but mentions key exploitation paths: Exploit the module loader to read host files Target credential paths: , Permission requirements: role with or permissions

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ZITADEL Actions V1 Sandbox Escape & Host File Read via require() [CVE-2026-89027]

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