FastGPT: sandbox escape to RCE - code-sandbox regex /\bimport\s*\(/ is bypassable

published 2026-05-29 5 mo ago modified 2026-07-22 3 mo ago also EUVD-2026-33431

cvss: 6.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits: 0; none known

FastGPT is an AI Agent building platform. Prior to 4.15.0-beta1, the JavaScript sandbox worker at projects/code-sandbox/src/pool/worker.ts:356 blocks dynamic import() with the regex /\bimport\s*\(/.test(code). JavaScript syntax accepts a block comment between import and (; the regex matches only ASCII whitespace, and the bytes /, *, *, / are not in the \s character class. The payload import/**/("child_process") parses as a syntactically valid dynamic import that the regex does not detect. Because import() is not wrapped by the safeRequire Proxy (which only proxies require), the attacker loads child_process and calls execSync - arbitrary command execution as uid=100(sandbox) inside the sandbox container. This vulnerability is fixed in 4.15.0-beta1.

Patch / fix

fixed in 1

fastgpt fastgpt 4.15.0-beta1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-06-01)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/labring/FastGPT/security/advisories/GHSA-f5mq-qxm4-5mvc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Affected products

labring FastGPT

Classification

Weakness

CWE-94 Improper Control of Generation of Code
CWE-184 Incomplete List of Disallowed Inputs

References

github.com /labring/FastGPT/security/advisories/GHSA-f5mq-qxm4-5mvc
exploit

Sources

CVE List CVE-2026-44287
NVD CVE-2026-44287

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary