What’s Vulnerable › Vulnerabilities

CVE-2026-100640: SiYuan before v3.8.4 Clipboard Data Disclosure via IPC

• Severity: medium (CVSS 4.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-26 · updated 2026-10-27
• Weakness: CWE-200

Description

SiYuan before v3.8.4 contains an authorization omission in the siyuan-get IPC handler that allows remote-kernel renderers to access native clipboard formats by invoking clipboardReadMathML, clipboardReadOffice, and clipboardReadWPS commands with matching plaintext. Attackers controlling remote renderer content can obtain MathML formulas, Office bytes, and WPS bytes from local clipboard during user-mediated paste operations.

Affected products

• siyuan-note siyuan: before 3.8.4 — fixed in 3.8.4

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.8.4. Check the vendor advisory for mitigations.

References

• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mjmm-hgmc-m7qf
• https://www.vulncheck.com/advisories/siyuan-before-3.8.4-clipboard-data-disclosure-via-ipc
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mjmm-hgmc-m7qf

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