# CVE-2026-86016: VNote: Stored XSS via YAML Frontmatter Leading to Local File Read and Remote Exfiltration

> Attackers can execute stored JavaScript via YAML frontmatter in VNote, enabling local file reading and remote data exfiltration.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 13 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-vfhj-c636-h59x

## What is CVE-2026-86016?

CVE-2026-86016 is a high-severity cross-site scripting vulnerability in vnotex vnote, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

VNote is a note-taking platform. Prior to 4.3.0, VNote uses the assignment `preNode.innerHTML = p_metaData` in src/data/extra/web/js/markdownit.js to insert YAML frontmatter metadata into a pre element before the protectFromXss sanitization path runs. Opening an attacker-supplied Markdown note can therefore execute stored JavaScript in the file:// viewer context. Because QWebEngineSettings::LocalContentCanAccessRemoteUrls enables local content to access remote URLs, the script can read reachable local note files and transmit their contents to a remote server without further interaction after the note is opened. This issue is fixed in version 4.3.0.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-86016?


## How do I fix CVE-2026-86016?

No fix has been published for CVE-2026-86016 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-86016 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86016 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-86016 and fix it if it is affected.

What it is: CVE-2026-86016 is a high-severity cross-site scripting vulnerability in vnotex vnote, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, 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-2026-86016 exists.

Affected product: vnotex vnote. 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-2026-86016/ (Markdown: https://insights.sbomify.com/CVE-2026-86016/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86016
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86016
- OSV: https://osv.dev/vulnerability/CVE-2026-86016

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86016/
Summaries are generated and may contain mistakes; the official description above is the record.