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CVE-2026-26003 - Unnerved Formations

Description

FastGPT is an AI Agent building platform. From 4.14.0 to 4.14.5, attackers can directly access the plugin system through FastGPT/api/plugin/xxx without authentication, thereby threatening the plugin system. This may cause the plugin system to crash and the loss of plugin installation status, but it will not result in key leakage. For older versions, as there are only operation interfaces for obtaining information, the impact is almost negligible. This vulnerability is fixed in 4.14.5-fix.

Reference

https://github.com/labring/FastGPT/commit/0beb52a2f3dc4067aab011cc98122d1352823b0c https://github.com/labring/FastGPT/releases/tag/v4.14.5-fix https://github.com/labring/FastGPT/security/advisories/GHSA-wcrg-g824-9gfg

Remediation Guide for FastGPT Plugin Authentication Vulnerability (Versions 4.14.0–4.14.5)

  1. Identify Current Version
    Check the installed version of FastGPT by reviewing the application’s VERSION file, UI footer, or API response headers. If the version is between 4.14.0 and 4.14.5, proceed with remediation.

  2. Immediately Restrict Access
    Temporarily block access to the /api/plugin/ endpoint at the network or reverse proxy level (e.g., Nginx, Apache, Cloudflare) using IP whitelisting or authentication enforcement until patching is complete.

  3. Upgrade to Patched Version
    Upgrade FastGPT to version 4.14.5-fix or later. Follow the official upgrade instructions provided in the FastGPT documentation to ensure a clean and safe update.

  4. Validate Plugin Integrity
    After upgrading, verify the integrity of all installed plugins by comparing plugin checksums or signatures (if available) against known good values. Reinstall any corrupted or missing plugins.

  5. Review Access Logs
    Analyze server access logs for any suspicious or unauthorized requests to /api/plugin/ endpoints during the vulnerable period. Investigate and isolate any compromised systems if anomalies are found.

  6. Implement Authentication for Plugin API
    Ensure all /api/plugin/ endpoints require valid authentication tokens (e.g., JWT, API key) and enforce role-based access control (RBAC). Do not allow anonymous access to plugin management endpoints.

  7. Test in Staging Environment
    Before deploying the patch to production, test the upgraded version and plugin functionality in a staging environment to confirm no regression or disruption occurs.

  8. Monitor for Recurrence
    Enable audit logging and alerting on plugin API access attempts. Set up monitoring for unauthorized access patterns or unusual plugin modifications.

  9. Document and Communicate
    Update internal incident response documentation with details of the vulnerability, remediation steps taken, and lessons learned. Notify relevant stakeholders (e.g., DevOps, Security Team) of the resolution.

Context within ISO/IEC 27001 and NIST Frameworks

ISO/IEC 27001 Controls

  • A.9.4.1 – Access Control Policy
    The vulnerability stemmed from a failure to enforce access control policies on plugin management endpoints. ISO/IEC 27001 requires that access to information systems be restricted based on business and security requirements. The unauthenticated API endpoint violated this principle.

  • A.12.4.1 – Management of Technical Vulnerabilities
    The organization failed to promptly identify and remediate a known technical vulnerability in its software stack. This control mandates regular scanning, patch management, and timely remediation of vulnerabilities.

  • A.14.2.5 – Secure System Engineering Principles
    The plugin system was not designed with security by default—authentication should have been mandatory from the outset. This control emphasizes integrating security into system design and development lifecycles.

NIST SP 800-53 Controls

  • AU-2 (Event Logging)
    Inadequate logging of access to plugin endpoints hindered detection. NIST requires comprehensive audit trails for critical system components.

  • IA-5 (Authenticator Management)
    The absence of authentication on /api/plugin/ directly violated this control, which mandates strong authentication for all system access points.

  • SI-2 (Flaw Remediation)
    This vulnerability falls under SI-2, which requires organizations to identify and remediate flaws in a timely manner. The delayed patching from 4.14.0 to 4.14.5-fix represents a failure in flaw remediation processes.

  • SI-7 (Security Assessment and Authorization)
    The vulnerability should have been detected during pre-deployment security assessments. Continuous monitoring and authorization processes must include third-party or custom components like plugins.

  • CM-6 (Configuration Management)
    Lack of proper version control and patch management for FastGPT components indicates a failure in configuration management practices. Only approved, patched versions should be deployed.

Conclusion: This vulnerability highlights gaps in access control and patch management under both ISO 27001 and NIST frameworks. Remediation must align with controls for access, audit, configuration, and vulnerability management to ensure compliance and resilience.