CVE-2026-84301 FastGPT safe axios SSRF guard still allows DNS rebinding TOCTOU on protected outbound requests

What is CVE-2026-84301?

CVE-2026-84301 is a medium-severity server-side request forgery vulnerability in labring FastGPT, published on 22 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-918

Which versions are affected by CVE-2026-84301?

How do I fix CVE-2026-84301?

No fix has been published for CVE-2026-84301 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-84301 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-84301 exists.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6jwp-qf29-hpj9.