Vulnerability in Siyuan-Note Siyuan
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-9gpj-3rm3-x42m (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-2.1.0-before-3.8.4-cross-site-request-forge… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100642?
- CVE-2026-100642 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Origin Validation Error. CVSS score: 7.6/10. Published 2026-09-26.
- How severe is CVE-2026-100642?
- High severity. CVSS v3 base score is 7.6 out of 10.