CVE-2026-42344: Labring Fastgpt

Medium severity, CVSS 6.3. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Labring Fastgpt: up to and including 4.14.11

Published 2026-05-08. Last modified 2026-07-24.