---
id: CVE-2026-12328
title: >-
  Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11,
  Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151
summary: >-
  Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11,
  Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. Some of these bugs
  showed evidence of memory corruption and we presume that with enough effort
  some of these c…
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-120
  - CWE-825
vendor: mozilla
product: firefox
affected:
  - firefox < 115.37.0
  - firefox < 152.0
  - 'firefox >= 140.0, < 140.12.0'
  - thunderbird < 152.0.0
  - 'thunderbird >= 140.0, < 140.12.0'
patched:
  - firefox 140.12.0
  - thunderbird 140.12.0
published: '2026-06-16'
updated: '2026-07-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-12328'
references:
  - url: >-
      https://bugzilla.mozilla.org/buglist.cgi?bug_id=2029402%2C2038477%2C2039726%2C2041373%2C2042268%2C2042451%2C2042782%2C2042858%2C2042929%2C2042965%2C2043213
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-57/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-58/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-59/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-60/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-61/'
    label: security@mozilla.org
  - url: 'https://access.redhat.com/errata/RHSA-2026:27717'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:27733'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:27734'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:29940'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:30846'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:33445'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:36100'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:36101'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:36102'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:36103'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-12328'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2489218'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12328.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
epss: 0.00476
epssPercentile: 0.38503
ingestedAt: '2026-07-07T13:53:11.844Z'
---

## Overview

Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. 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 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

## Affected

- `firefox < 115.37.0`
- `firefox < 152.0`
- `firefox >= 140.0, < 140.12.0`
- `thunderbird < 152.0.0`
- `thunderbird >= 140.0, < 140.12.0`

## Remediation

Upgrade past the affected range:

- `firefox 140.12.0`
- `thunderbird 140.12.0`