CVE-2026-34585 SiYuan: Stored XSS in imported .sy.zip content leads to arbitrary command execution
Attackers can achieve remote code execution in the Electron client by tricking users into importing malicious .sy.zip files containing stored XSS payloads.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-34585?
CVE-2026-34585 is a high-severity cross-site scripting vulnerability in B3log Siyuan, published on 31 Mar 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
SiYuan is a personal knowledge management system. Prior to version 3.6.2, a vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import -> SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. This issue has been patched in version 3.6.2.
Which versions are affected by CVE-2026-34585?
3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260329142331-918d1bd9f967 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260329142331-918d1bd9f967 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260329142331-918d1bd9f967 |
Products include B3log Siyuan.
How do I fix CVE-2026-34585?
Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260329142331-918d1bd9f967 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-34585 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34585 exists.
Other vulnerabilities in B3log Siyuan
- CVE-2026-32938 SiYuan has an Arbitrary File Read in its Desktop Publish Service
- CVE-2026-33669 SiYuan has Arbitrary Document Reading within the Publishing Service
- CVE-2026-33670 SiYuan has directory traversal within its publishing service
- CVE-2026-32767 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API
- CVE-2024-53504 SQL injection in n/a
Sources
Also known as GHSA-ff66-236v-p4fg, GO-2026-5357.