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Fencer Intel
high 8.8

CVE-2026-41421 json

SiYuan Desktop Notification XSS Leads to Electron RCE

published 6mo ago modified 4mo ago also EUVD-2026-25614

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

SiYuan is an open-source personal knowledge management system. Prior to 3.6.5, SiYuan desktop renders notification messages as raw HTML inside an Electron renderer. The notification route POST /api/notification/pushMsg accepts a user-controlled msg value, forwards it through the backend broadcast layer, and the frontend inserts it into the DOM with insertAdjacentHTML(...) at message.ts. On desktop builds, this is not limited to ordinary XSS. Electron windows are created with nodeIntegration: true, contextIsolation: false, and webSecurity: false at main.js. As a result, JavaScript executed from the notification sink can directly access Node APIs and escalate to desktop code execution. This vulnerability is fixed in 3.6.5.

Patch / fix

  • b3log siyuan 3.6.5

Is CVE-2026-41421 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
6mo ago

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/siyuan-note/siyuan/security/advisories/GHSA-grjj-6f6g-cq8q referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • siyuan-note siyuan

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.