CVE-2026-100642 (CVSS 7.6)

Description

SiYuan versions from v2.1.0 before v3.8.4 contain a cross-site request forgery vulnerability in the CheckAuth lock-screen pass-through branch that grants administrator access to loopback requests without validating Origin headers. Attackers can craft malicious web pages that force victims to terminate the kernel process, read workspace configuration and proxy settings, and trigger administrative actions via zero-credential cross-origin requests from the victim's browser.

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CVSS v3.1 Score

7.6

HIGH

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

EPSS — Exploit Prediction

0.0011

Probability of exploitation

0.01%

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-346 CWE-346

References

Other References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-9gpj-3rm3-x42m https://www.vulncheck.com/advisories/siyuan-2.1.0-before-3.8.4-cross-site-request-forgery-via-checkauth https://github.com/siyuan-note/siyuan/security/advisories/GHSA-9gpj-3rm3-x42m

Frequently Asked Questions

What is CVE-2026-100642? +

SiYuan versions from v2.1.0 before v3.8.4 contain a cross-site request forgery vulnerability in the CheckAuth lock-screen pass-through branch that grants administrator access to loopback requests without validating Origin headers. Attackers can craft malicious web pages that force victims to terminate the kernel process, read workspace configuration and proxy settings, and trigger administrative actions via zero-credential cross-origin requests from the victim's browser. It has a CVSS v3.1 base score of 7.6 (HIGH).

How severe is CVE-2026-100642? +

CVE-2026-100642 has a CVSS v3.1 score of 7.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0011, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-100642? +

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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