High 8.0Published Sep 26, 2026

CVE-2026-100641SiYuan before v3.8.4 Stored XSS via Unescaped Flashcard Content

Updated under an hour ago (Oct 26, 2026, 4:20 PM ET)

Does this affect you?

It affects siyuan-note siyuan. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.53%, higher than 43% of scored CVEs.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for siyuan-note siyuan

Exploited in the last 30 days

SiYuan before v3.8.4 does not HTML-escape stored flashcard block content before interpolating it into the card-manager list markup. Block content returned by /api/riff/getRiffCards is inserted into a card item template in app/src/card/viewCards.ts and assigned to listElement.innerHTML, so content such as <img src=invalid onerror=...> becomes an executable event-handler attribute. Because the SiYuan desktop (Electron) main window is created with nodeIntegration enabled and contextIsolation disabled, an administrator who opens the card manager on a workspace containing attacker-supplied flashcard content (for example introduced through contribution or import) executes the attacker's script in a privileged renderer, which can lead to arbitrary code execution on the host. The affected endpoint remains behind authentication and administrator-role checks; this is an untrusted-content-to-privileged-renderer issue, not an authorization bypass.

CVSS: 8.0 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.53% (percentile 43)
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Oct 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

siyuan-note siyuan siyuan_note:siyuan (from the name)	before 3.8.4; 3.8.4 not affected	CNA record

References

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-2mmf-4xwm-55rm	vendor-advisory
https://github.com/siyuan-note/siyuan/commit/1ecb1c07de497ff03b585536fe5579291754d96b	patch
https://github.com/siyuan-note/siyuan/commit/48c354e7de130aaada9d7120125bbc768344fd3b	patch
https://github.com/siyuan-note/siyuan/commit/41b14025b4ac4a8379d1200580344ca18ad152b7	patch
https://github.com/siyuan-note/siyuan/commit/8641553a1f07374001902d3ce773285db1292b2d	patch
https://www.vulncheck.com/advisories/siyuan-before-3.8.4-stored-xss-via-unescaped-flashcard-content	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.