Vulnerability · Published Sep 26, 2026 · Assigned by VulnCheck

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

Medium 4.7

In plain English

A medium-severity information exposure in siyuan from siyuan-note. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).

Severity (CVSS 3.1)4.7Medium

Exploit odds (30 days)0.2%top 84.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
siyuan-note	siyuan	0 – before 3.8.4

Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N

References

GitHub Security Advisory (GHSA-mjmm-hgmc-m7qf) vendor-advisory
VulnCheck Advisory: SiYuan before v3.8.4 Clipboard Data Disclosure via IPC third-party-advisory