---
id: CVE-2025-3034
title: Memory safety bugs present in Firefox 136 and Thunderbird 136
summary: >-
  Memory safety bugs present in Firefox 136 and Thunderbird 136. 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
  vulnerabili…
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-787
vendor: mozilla
product: firefox
affected:
  - firefox < 137.0
  - thunderbird < 137.0
patched:
  - firefox 137.0
  - thunderbird 137.0
published: '2025-04-01'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T18:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-3034'
references:
  - url: >-
      https://bugzilla.mozilla.org/buglist.cgi?bug_id=1894100%2C1934086%2C1950360
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-20/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-23/'
    label: security@mozilla.org
tags:
  - nvd
epss: 0.0046
epssPercentile: 0.37557
ingestedAt: '2026-09-30T18:17:24.432Z'
---

## Overview

Memory safety bugs present in Firefox 136 and Thunderbird 136. 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 137 and Thunderbird 137.

## Affected

- `firefox < 137.0`
- `thunderbird < 137.0`

## Remediation

Upgrade past the affected range:

- `firefox 137.0`
- `thunderbird 137.0`