labring FastGPT up to 4.15.1 Request Interceptor axios.ts isInternalAddress dns rebinding

Summaryinfo

A vulnerability was found in labring FastGPT up to 4.15.1. It has been declared as critical. Affected by this vulnerability is the function isInternalAddress of the file packages/service/common/api/axios.ts of the component Request Interceptor. The manipulation results in dns rebinding. This vulnerability is known as CVE-2026-84301. It is possible to launch the attack remotely. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in labring FastGPT up to 4.15.1. Affected is the function isInternalAddress of the file packages/service/common/api/axios.ts of the component Request Interceptor. The manipulation with an unknown input leads to a dns rebinding vulnerability. CWE is classifying the issue as CWE-350. The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

FastGPT is an open-source LLM platform for building AI applications on a knowledge base. Prior to 4.15.2, the safe Axios request interceptor in packages/service/common/api/axios.ts validates a hostname with isInternalAddress() before a later HTTP connection performs an independent DNS lookup, creating a DNS rebinding window, allowing an attacker-controlled hostname to resolve publicly during the check and to a loopback, private, link-local, or metadata address during connection. An authenticated attacker who can supply a URL to a safe-Axios-backed HTTP tool, workflow HTTP node, external file fetch, or other server-side integration can use this time-of-check/time-of-use gap to reach services that direct private-address inputs would block. The same independent re-resolution occurs after manual redirect hops because each redirect target is checked before a separate connection lookup. This issue is fixed in version 4.15.2.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-84301 since 09/01/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1583.002.

Upgrading to version 4.15.2 eliminates this vulnerability.

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Productinfo

Vendor

• labring

Name

• FastGPT

Version

• 4.15.0
• 4.15.1

Website

• Product: https://github.com/labring/FastGPT/

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