CVE-2026-41518

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.

CVSS v3.1 Score

7.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.10%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

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

Frequently Asked Questions

What is CVE-2026-41518? +

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. It has a CVSS v3.1 base score of 7.6 (HIGH).

How severe is CVE-2026-41518? +

CVE-2026-41518 has a CVSS v3.1 score of 7.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-41518? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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