---
id: CVE-2025-1937
title: >-
  Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR
  115.20, Firefox ESR 128.7, and Thunderbird 128.7
summary: >-
  Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR
  115.20, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed
  evidence of memory corruption and we presume that with enough effort some of
  these could …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-1260
vendor: mozilla
product: firefox
affected:
  - firefox < 115.21.0
  - firefox < 128.8.0
  - firefox < 135.0
  - thunderbird < 128.8.0
  - 'thunderbird >= 129.0, < 136.0'
patched:
  - firefox 135.0
  - thunderbird 136.0
published: '2025-03-04'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T18:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-1937'
references:
  - url: 'https://bugzilla.mozilla.org/buglist.cgi?bug_id=1938471%2C1940716'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-14/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-15/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-16/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-17/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-18/'
    label: security@mozilla.org
  - url: 'http://www.openwall.com/lists/oss-security/2025/03/10/6'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00562
epssPercentile: 0.44633
ingestedAt: '2026-09-30T18:17:24.428Z'
---

## Overview

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, and Thunderbird 128.7. 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 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

## Affected

- `firefox < 115.21.0`
- `firefox < 128.8.0`
- `firefox < 135.0`
- `thunderbird < 128.8.0`
- `thunderbird >= 129.0, < 136.0`

## Remediation

Upgrade past the affected range:

- `firefox 135.0`
- `thunderbird 136.0`