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.
- 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
- None listed
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
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.
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-2026-86016 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86016 exists.
Sources
Also known as GHSA-vfhj-c636-h59x.