CVE-2026-42344

medium

Description

FastGPT is an AI Agent building platform. In versions 4.14.11 and prior, FastGPT's isInternalAddress() function in packages/service/common/system/utils.ts is vulnerable to DNS rebinding (TOCTOU — Time-of-Check to Time-of-Use). The function resolves the hostname via dns.resolve4()/dns.resolve6() and checks resolved IPs against private ranges, but the actual HTTP request happens in a separate call with a new DNS resolution, allowing the DNS record to change between validation and fetch. At time of publication, there are no publicly available patches.

References

https://github.com/labring/FastGPT/security/advisories/GHSA-cc8x-jrqv-hmwh

Details

Source: Mitre, NVD

Published: 2026-05-08

Updated: 2026-05-08

Risk Information

CVSS v2

Base Score: 4.9

Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 6.3

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Severity: Medium