SiYuan before v3.8.4 Stored XSS via Unescaped Flashcard Content
Summary
| CVE | CVE-2026-100641 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-26 14:16:46 UTC |
| Updated | 2026-09-26 14:16:46 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 8.6 HIGH from [email protected]
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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
Problem Types: CWE-79 | CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 8.6 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 8.6 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| 3.1 | [email protected] | Primary | 8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
LowUser Interaction
PassiveConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
RequiredScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Siyuan-note | Siyuan | affected 3.8.4 semver | Not specified |
| CNA | Siyuan-note | Siyuan | unaffected 3.8.4 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/siyuan-note/siyuan/commit/41b14025b4ac4a8379d1200580344ca18ad... | [email protected] | github.com | |
| github.com/siyuan-note/siyuan/commit/48c354e7de130aaada9d7120125bbc76834... | [email protected] | github.com | |
| github.com/siyuan-note/siyuan/security/advisories/GHSA-2mmf-4xwm-55rm | [email protected] | github.com | |
| www.vulncheck.com/advisories/siyuan-before-3.8.4-stored-xss-via-unescaped-flash... | [email protected] | www.vulncheck.com | |
| github.com/siyuan-note/siyuan/commit/8641553a1f07374001902d3ce773285db12... | [email protected] | github.com | |
| github.com/siyuan-note/siyuan/commit/1ecb1c07de497ff03b585536fe557929175... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: rexpository (en)
There are currently no legacy QID mappings associated with this CVE.