CVE-2026-55570

9.0 CRITICAL 0.4% exploit odds Fix listed XSS Library

What it is

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, it does not escape the untrusted fields (name, version, author, description) when they are serialized into the data-obj HTML attribute of each marketplace card. Because the attribute is single-quoted and the value is produced with JSON.stringify() (which does not escape ', <, or >), a package whose name contains a single quote breaks out of the attribute and injects arbitrary HTML. In the desktop client the main BrowserWindow runs with nodeIntegration: true, contextIsolation: false, so the injected markup escalates from DOM XSS to arbitrary OS command execution. This is the same root cause and same impact as the original advisory, reached through a sibling sink the patch did not cover. This vulnerability is fixed in 3.7.0.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-24 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-25 23:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 9.0 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-24 22:16 UTC
Last modified: 2026-10-25 23:10 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-79 · Cross-site scripting
Record status: Deferred

Attack profile CVSS 3.1 · 9.0

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: Required
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-55570.md and follow it. Check whether this project is affected by CVE-2026-55570. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record