---
id: CVE-2025-49710
title: >-
  An integer overflow was present in `OrderedHashTable` used by the JavaScript
  engine
summary: >-
  An integer overflow was present in `OrderedHashTable` used by the JavaScript
  engine. This vulnerability was fixed in Firefox 139.0.4.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-190
vendor: mozilla
product: firefox
affected:
  - firefox < 139.0.4
patched:
  - firefox 139.0.4
published: '2025-06-11'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T18:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-49710'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1970095'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-47/'
    label: security@mozilla.org
tags:
  - nvd
epss: 0.00744
epssPercentile: 0.53003
ingestedAt: '2026-09-30T18:17:24.442Z'
---

## Overview

An integer overflow was present in `OrderedHashTable` used by the JavaScript engine. This vulnerability was fixed in Firefox 139.0.4.

## Affected

- `firefox < 139.0.4`

## Remediation

Upgrade past the affected range:

- `firefox 139.0.4`