CVE-2026-105784 Joplin whiteboard card rendering allows CSS injection into application chrome
Attackers can inject CSS into Joplin's whiteboard view to modify UI and potentially disclose data via crafted notes.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-105784?
CVE-2026-105784 is a medium-severity cross-site scripting vulnerability in laurent22 joplin, published on 5 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.13, selecting a note containing a jsoncanvas fence causes the whiteboard text and file-node components in packages/app-desktop/gui/NoteEditor/NoteBody/WhiteboardEditor/nodes/TextNode.tsx and packages/app-desktop/gui/NoteEditor/NoteBody/WhiteboardEditor/nodes/FileNode.tsx to render card content with the full Markdown renderer. The components insert the resulting HTML into the main application document through dangerouslySetInnerHTML. A malicious note can inject style elements and remote CSS imports that modify trusted application chrome, signal when the note is opened, and potentially disclose exposed attribute values. Content Security Policy blocks inline script execution, so the supported impact is CSS injection and UI redressing rather than code execution. This issue is fixed in version 3.7.13.
Weakness: CWE-79
Which versions are affected by CVE-2026-105784?
How do I fix CVE-2026-105784?
No fix has been published for CVE-2026-105784 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-105784 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105784 exists.
Sources
Also known as GHSA-6h4j-86j4-x4q4.