---
id: "GHSA-x8gv-g2g3-65fj"
kind: "vulnerability"
aliases: ["GHSA-x8gv-g2g3-65fj", "GO-2026-6657"]
title: "SiYuan Agent Tools SSRF via DNS-Rebinding TOCTOU (Bypass of CheckHostSSRF) in github.com/siyuan-note/siyuan/kernel"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "github.com/siyuan-note/siyuan/kernel", "fixed": ["0.0.0-20260813142806-dd2778b70d02"], "affected": "< 0.0.0-20260813142806-dd2778b70d02", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["agent-tools", "go", "package", "self-hosted", "siyuan"]
not_affected_if: ["unknown"]
published_at: "2026-10-07T14:10:14+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T20:20:13+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6657", "first_seen_at": "2026-10-23T19:13:08+00:00"}]
---

# SiYuan Agent Tools SSRF via DNS-Rebinding TOCTOU (Bypass of CheckHostSSRF) in github.com/siyuan-note/siyuan/kernel

SiYuan's Agent Tools in the kernel package have an SSRF flaw: a DNS-rebinding time-of-check/time-of-use race lets a request bypass the CheckHostSSRF host check. An attacker can make the server reach internal hosts it should not contact.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/siyuan-note/siyuan/kernel affected < 0.0.0-20260813142806-dd2778b70d02 fixed 0.0.0-20260813142806-dd2778b70d02

## How to check

Run go list -m github.com/siyuan-note/siyuan/kernel to see the pinned pseudo-version.

## Fix

Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260813142806-dd2778b70d02 or later.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6657

## From the sources

SiYuan Agent Tools SSRF via DNS-Rebinding TOCTOU (Bypass of CheckHostSSRF) in github.com/siyuan-note/siyuan/kernel

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_