# CVE-2026-66395: SiYuan Desktop reflected XSS to RCE in bazaar plugin handler

Source: https://junglewise.ai/threats/cve-2026-66395-siyuan-desktop-reflected-xss-to-rce-in-bazaar-plugin-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-27. Updated: 2026-07-27  
License: CC BY 4.0 with a link back

CVE-2026-66395 · Severity: critical · CVSS 9.6 · Published 2026-07-27

SiYuan, a personal knowledge management and note-taking application, is vulnerable to a security flaw that allows attackers to take complete control of a user's computer. By tricking a user into clicking a specially crafted link (starting with 'siyuan://'), an attacker can execute malicious commands on the victim's operating system. This could lead to the theft of private notes, data deletion, or the installation of malware.

Technologies: [SiYuan](https://junglewise.ai/threats/technologies/siyuan). Vendors: [SiYuan](https://junglewise.ai/threats/vendors/siyuan).

## Quick answers

**Is CVE-2026-66395 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-66395 being exploited in the wild.

**How severe is CVE-2026-66395?** Critical severity, with a CVSS score of 9.6, published 27 July 2026.

**Which products and versions are affected?** SiYuan < 3.7.2.

**Is there a fix for CVE-2026-66395?** A patch was published on 2026-07-27: Vendor released version 3.7.2 to address the issue Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-66395 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-66395?** Check whether you run SiYuan at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A reflected cross-site scripting (XSS) vulnerability exists in the SiYuan desktop application's handling of the 'siyuan://' protocol. The application fails to sanitize the plugin name segment in the 'bazaar/plugins/<name>/readme' path, which is decoded and passed to the 'showMessage' function. This function uses 'insertAdjacentHTML' to render the input in an Electron renderer configured with 'nodeIntegration: true' and 'contextIsolation: false'. An attacker can leverage this to execute arbitrary Node.js commands and achieve Remote Code Execution (RCE) on the host OS. The vulnerability is patched in version 3.7.2.

## Affected products

- siyuan-note SiYuan < 3.7.2

## Timeline

- 2026-07-13: advisory: GitHub Security Advisory published
- 2026-07-27: disclosed: NVD publication date
- 2026-07-27: patched: Vendor released version 3.7.2 to address the issue

## References

- [https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6gx2-8gcr-x83f](https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6gx2-8gcr-x83f)
- [https://www.vulncheck.com/advisories/siyuan-desktop-before-reflected-xss-to-rce-via-siyuan-protocol](https://www.vulncheck.com/advisories/siyuan-desktop-before-reflected-xss-to-rce-via-siyuan-protocol)

## Related threats

- [SiYuan path traversal in web fetch](https://junglewise.ai/threats/cve-2026-126776-siyuan-3-7-0-before-3-8-10-on-windows-contains-a-path-traversal)
- [SiYuan publish filter information disclosure in local storage](https://junglewise.ai/threats/go-2026-6836-siyuan-the-publish-filter-for-local-storage-returns-the-7f022e62)
- [SiYuan path traversal via GLOBALROOT alias bypass](https://junglewise.ai/threats/cve-2026-118680-siyuan-3-8-7-through-3-8-8-fails-to-normalize-windows-globalroot)
- [SiYuan SQL injection in history search](https://junglewise.ai/threats/cve-2026-116170-siyuan-before-v3-8-7-contains-an-sql-injection-vulnerability)
- [SiYuan cross-site scripting in /check-auth redirect](https://junglewise.ai/threats/cve-2026-116167-siyuan-from-2-9-0-before-3-8-7-contains-a-cross-site-scripting)