Medium severity · published Sep 26, 2026
CVE-2026-100640
SiYuan before v3.8.4 Clipboard Data Disclosure via IPC
4.7
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
None
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
siyuan · siyuan-note
before 3.8.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-100640
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-100640
vendor-advisory
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mjmm-hgmc-m7qf
third-party-advisory
https://www.vulncheck.com/advisories/siyuan-before-3.8.4-clipboard-data-disclosure-via-ipc
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