FastGPT Python Sandbox Bypass of File-Write Restriction
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
FastGPT is an AI Agent building platform. In 4.14.7 and earlier, FastGPT's Python Sandbox (fastgpt-sandbox) includes guardrails intended to prevent file writes (static detection + seccomp). These guardrails are bypassable by remapping stdout (fd 1) to an arbitrary writable file descriptor using fcntl. After remapping, writing via sys.stdout.write() still satisfies the seccomp rule write(fd==1), enabling arbitrary file creation/overwrite inside the sandbox container despite the intended no file writes restriction.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-32128
References
More labring vulnerabilities
- TI-2026-30610 FastGPT: Unauthenticated Remote Code Execution (RCE) via code-server Misconfiguration in agent-sandbox CVSS 3.1CRITICAL 9.8
- TI-2026-48466 FastGPT: Unauthenticated WeChat channel hijack and denial of service via shareId-only authorization CVSS 4.0CRITICAL 9.3
- TI-2026-44161 FastGPT: Unauthenticated cross-tenant data access via forgeable plugin-invoke JWT (default INVOKE_TOKEN_SECRET='token') CVSS 4.0HIGH 8.8
- TI-2026-44148 Incorrect authorization in labring FastGPT CVSS 3.1HIGH 7.7
- TI-2026-39440 FastGPT: SSRF in HTTP-tool OpenAPI schema importer via SwaggerParser $ref (bypasses the isInternalAddress guard) CVSS 3.1HIGH 7.7
- TI-2026-30646 FastGPT: Uncontrolled Resource Consumption leading to Sandbox Exhaustion CVSS 4.0MEDIUM 6.3
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences