CVE-2026-74902 PUBLISHED

SiYuan before v3.7.4 XSS-to-RCE via malicious filename upload

Assigner: VulnCheck
Reserved: 17.08.2026 Published: 18.08.2026 Updated: 18.08.2026

SiYuan before v3.7.4 contains a cross-site scripting vulnerability in the file upload validation flow that fails to escape filenames before inserting them into HTML via insertAdjacentHTML. Attackers can craft a malicious filename containing script payloads that execute with full OS command access when a user drags, drops, or pastes the file into the editor.

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CVSS Score: 9.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Local	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	High	Integrity	High
Attack Requirements	None	Availability	High	Availability	High
Privileges Required	None
User Interaction	Passive

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CVSS Score: 8.6

Attack Vector	Local	Scope	Changed
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	Required	Availability Impact	High

CVSS 3.1

Product Status

Vendor	siyuan-note
Product	siyuan
Versions	Default: unaffected affected from 0 to 3.7.4 (excl.) Version 3.7.4 is unaffected

Credits

alham-rizvi reporter

References

Problem Types

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE