# CVE-2026-86016: VNote stored XSS in YAML frontmatter

Source: https://junglewise.ai/threats/cve-2026-86016-vnote-is-a-note-taking-platform-prior-to-4-3-0-vnote-uses-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-86016 · Severity: high · CVSS 8.2 · Published 2026-10-13

VNote is a note-taking application that allows users to create and edit Markdown documents. Prior to version 4.3.0, the application improperly handles YAML frontmatter metadata when rendering notes, allowing malicious Markdown files to execute arbitrary JavaScript. An attacker can craft a note file that, when opened, executes JavaScript with access to read local files and transmit their contents to a remote server without any additional user interaction.

Technologies: [Vnotex vNote](https://junglewise.ai/threats/technologies/vnote). Vendors: [Vnotex](https://junglewise.ai/threats/vendors/vnotex).

## Quick answers

**Is CVE-2026-86016 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86016 being exploited in the wild.

**How severe is CVE-2026-86016?** High severity, with a CVSS score of 8.2, published 13 October 2026.

**Which products and versions are affected?** Vnotex vNote before 4.3.0.

**Is there a fix for CVE-2026-86016?** Yes: fixed in 4.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86016 attacked?** It is attacked over the network or with local access.

**Am I affected by CVE-2026-86016?** Check whether you run Vnotex vNote at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 4.3.0

## Technical details

The vulnerability is a stored cross-site scripting (XSS) flaw in markdownit.js where YAML frontmatter is inserted via innerHTML assignment before XSS sanitization occurs. When a user opens an attacker-supplied Markdown note in the file:// context, the JavaScript executes with the ability to read local files due to QWebEngineSettings::LocalContentCanAccessRemoteUrls being enabled, allowing data exfiltration. The fix changes the assignment from innerHTML to textContent to treat the YAML as plaintext.

## Affected products

- vnotex VNote before 4.3.0

## Timeline

- 2026-10-13: disclosed
- 2026-07-25: patched: Version 4.3.0 released

## References

- [https://github.com/vnotex/vnote/commit/7371efde531312eb24beb982fb5fdd73469cb171](https://github.com/vnotex/vnote/commit/7371efde531312eb24beb982fb5fdd73469cb171)
- [https://github.com/vnotex/vnote/releases/tag/v4.3.0](https://github.com/vnotex/vnote/releases/tag/v4.3.0)

## Related threats

- [VNote external program argument injection](https://junglewise.ai/threats/cve-2026-86022-vnote-is-a-note-taking-platform-prior-to-4-3-0-sessionconfig)
- [vnotex vNote cross-site scripting in YAML Frontmatter](https://junglewise.ai/threats/cve-2026-15505-vnotex-vnote-cross-site-scripting-in-yaml-frontmatter)