CVE-2026-100641

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.7% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-26 02:32 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-09-26 14:16 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-05 16:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.7% in the next 30 days (EPSS).
• Severity: 8.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-26 14:16 UTC

Last modified

2026-10-05 16:17 UTC

Exploit probability

0.7% · EPSS, next 30 days

Weakness

CWE-79 · Cross-site scripting

Record status

Deferred

Attack profile CVSS 4.0 · 8.6

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

Low

User interaction

Passive

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-100641.md and follow it. Check whether this project is affected by CVE-2026-100641. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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