CVE-2026-100643: XSS (CVSS 8)

Description

SiYuan versions before v3.8.4 fail to properly escape four stored Attribute View values in textarea elements, allowing authenticated attackers to inject JavaScript by modifying field descriptions, template sources, select option descriptions, or footer calculation templates. Attackers can execute stored JavaScript when other users open affected database menus, and in the Electron desktop app with nodeIntegration enabled, this leads to command execution with SiYuan process privileges.

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CVSS v3.1 Score

8.0

HIGH

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

EPSS — Exploit Prediction

0.0042

Probability of exploitation

0.34%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-h3p6-c22r-fx2j https://www.vulncheck.com/advisories/siyuan-before-3.8.4-stored-xss-via-attribute-view-textarea https://github.com/siyuan-note/siyuan/security/advisories/GHSA-h3p6-c22r-fx2j

Frequently Asked Questions

What is CVE-2026-100643? +

SiYuan versions before v3.8.4 fail to properly escape four stored Attribute View values in textarea elements, allowing authenticated attackers to inject JavaScript by modifying field descriptions, template sources, select option descriptions, or footer calculation templates. Attackers can execute stored JavaScript when other users open affected database menus, and in the Electron desktop app with nodeIntegration enabled, this leads to command execution with SiYuan process privileges. It has a CVSS v3.1 base score of 8.0 (HIGH).

How severe is CVE-2026-100643? +

CVE-2026-100643 has a CVSS v3.1 score of 8.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0042, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-100643? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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