CVE-2026-74902

critical

Description

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.

References

https://www.vulncheck.com/advisories/siyuan-before-xss-to-rce-via-malicious-filename-upload

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jf56-jrhq-j2qp

Details

Source: Mitre, NVD

Published: 2026-08-18

Updated: 2026-08-26

Risk Information

CVSS v2

Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 8.6

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

Severity: High

CVSS v4

Base Score: 9.3

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

Severity: Critical

EPSS

EPSS: 0.00147