CVE-2026-74902

critical · 9.3

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.

9.3

CVSS

0.2%

EPSS (exploit prob.)

9th

EPSS percentile

2026-08-18

Published

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-79

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jf56-jrhq-j2qp
https://www.vulncheck.com/advisories/siyuan-before-xss-to-rce-via-malicious-filename-upload

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-74902