CVE-2026-40922CWE-79

SiYuan: Incomplete sanitization of bazaar README allows stored XSS via iframe srcdoc (incomplete fix for CVE-2026-33066)

Medium · published April 16, 2026

CVSS v4.0
5.3
EPSS
0%
Percentile
30.4
In the wild
Unconfirmed
What it is

SiYuan is an open-source personal knowledge management system. In versions 3.6.1 through 3.6.3, a prior fix for XSS in bazaar README rendering (incomplete fix for CVE-2026-33066) enabled the Lute HTML sanitizer, but the sanitizer does not block iframe tags, and its URL-prefix blocklist does not effectively filter srcdoc attributes which contain raw HTML rather than URLs. A malicious bazaar package author can include an iframe with a srcdoc attribute containing embedded scripts in their README. When other users view the package in SiYuan's marketplace UI, the payload executes in the Electron context with full application privileges, enabling arbitrary code execution on the user's machine. This issue has been fixed in version 3.6.4.

The record
Technical detail
CVSS v4.0
5.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
EPSS
0.00377 · 30.4th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-04-16T23:14Z
EPSS history
Timeline
  • 16 APR 23:14Z
    SiYuan: Incomplete sanitization of bazaar README allows stored XSS via iframe srcdoc (incomplete fix for CVE-2026-33066)
    cvelistv5