---
id: CVE-2025-9185
title: >-
  Memory safety bugs present in Firefox ESR 115.26, Firefox ESR 128.13,
  Thunderbird ESR 128.13, Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141
  and Thunderbird 141
summary: >-
  Memory safety bugs present in Firefox ESR 115.26, Firefox ESR 128.13,
  Thunderbird ESR 128.13, Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141
  and Thunderbird 141. Some of these bugs showed evidence of memory corruption
  and we presu…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-119
vendor: mozilla
product: firefox
affected:
  - firefox < 115.27.0
  - firefox < 142.0
  - 'firefox >= 128.0, < 128.14.0'
  - 'firefox >= 140.0, < 140.2.0'
  - thunderbird < 128.14.0
  - thunderbird < 142.0
  - 'thunderbird >= 140.0, < 140.2.0'
patched:
  - firefox 140.2.0
  - thunderbird 140.2.0
published: '2025-08-19'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T18:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-9185'
references:
  - url: >-
      https://bugzilla.mozilla.org/buglist.cgi?bug_id=1970154%2C1976782%2C1977166
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-64/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-65/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-66/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-67/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-70/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-71/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-72/'
    label: security@mozilla.org
  - url: 'https://lists.debian.org/debian-lts-announce/2025/08/msg00016.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/08/msg00018.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00489
epssPercentile: 0.39751
ingestedAt: '2026-09-30T18:17:24.458Z'
---

## Overview

Memory safety bugs present in Firefox ESR 115.26, Firefox ESR 128.13, Thunderbird ESR 128.13, Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141 and Thunderbird 141. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 142, Firefox ESR 115.27, Firefox ESR 128.14, Firefox ESR 140.2, Thunderbird 142, Thunderbird 128.14, and Thunderbird 140.2.

## Affected

- `firefox < 115.27.0`
- `firefox < 142.0`
- `firefox >= 128.0, < 128.14.0`
- `firefox >= 140.0, < 140.2.0`
- `thunderbird < 128.14.0`
- `thunderbird < 142.0`
- `thunderbird >= 140.0, < 140.2.0`

## Remediation

Upgrade past the affected range:

- `firefox 140.2.0`
- `thunderbird 140.2.0`