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.

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.

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

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. 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

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