Vulnerability · Published Mar 11, 2026 · Assigned by GitHub_M
CVE-2026-32128FastGPT Python Sandbox Bypass of File-Write Restriction
Medium 6.3
In plain English
A medium-severity security flaw in FastGPT from labring. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
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.
Affected products (as reported)
Weakness: CWE-184 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
References
- https://github.com/labring/FastGPT/security/advisories/GHSA-6hw6-mxrm-v6wj x_refsource_CONFIRM