# CVE-2026-82234: SiYuan before v3.8.1 SSRF via DNS-Rebinding TOCTOU

> Attackers can exploit DNS rebinding in SiYuan's agent tools to bypass SSRF protections and access internal services or cloud metadata.

- **Severity:** High 8.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-g42r-m263-958h, GHSA-x8gv-g2g3-65fj, GO-2026-6657

## What is CVE-2026-82234?

CVE-2026-82234 is a high-severity server-side request forgery vulnerability in siyuan-note siyuan, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

SiYuan versions before v3.8.1 contain a server-side request forgery vulnerability in the http_request and web_fetch agent tools that perform DNS resolution only at guard time without validating the connect-time resolution. Attackers can use DNS rebinding to answer the guard resolution with a public IP and the connect resolution with a private or metadata IP, bypassing the SSRF defense to access cloud instance metadata and internal services.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-82234?

3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260813142806-dd2778b70d02 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260813142806-dd2778b70d02 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260813142806-dd2778b70d02 |

## How do I fix CVE-2026-82234?

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

## Is CVE-2026-82234 being exploited?

There is no known exploitation of CVE-2026-82234 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82234 and fix it if it is affected.

What it is: CVE-2026-82234 is a high-severity server-side request forgery vulnerability in siyuan-note siyuan, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-82234 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260813142806-dd2778b70d02
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260813142806-dd2778b70d02
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260813142806-dd2778b70d02

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-82234/ (Markdown: https://insights.sbomify.com/CVE-2026-82234/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82234
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82234
- OSV: https://osv.dev/vulnerability/CVE-2026-82234

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82234/
Summaries are generated and may contain mistakes; the official description above is the record.