# 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.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N`)
- **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 available:** No
- **Published:** 5 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-6h4j-86j4-x4q4

## 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 (Improper Neutralization of Input During Web Page Generation)

## 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.

## Is CVE-2026-105784 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105784 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105784 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105784 exists.

Affected product: laurent22 joplin. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-105784/ (Markdown: https://insights.sbomify.com/CVE-2026-105784/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105784
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105784
- OSV: https://osv.dev/vulnerability/CVE-2026-105784

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105784/
Summaries are generated and may contain mistakes; the official description above is the record.