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.
- 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
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
Which versions are affected by CVE-2026-82234?
3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel.
| Package | 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.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-82234 being exploited?
There is no known exploitation of CVE-2026-82234 in the wild and no public exploit code.
Sources
Also known as GHSA-g42r-m263-958h, GHSA-x8gv-g2g3-65fj, GO-2026-6657.