---
id: CVE-2025-1936
title: 'jar: URLs retrieve local file content packaged in a ZIP archive'
summary: >-
  jar: URLs retrieve local file content packaged in a ZIP archive. The null and
  everything after it was ignored when retrieving the content from the archive,
  but the fake extension after the null was used to determine the type of
  content. …
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-158
vendor: mozilla
product: firefox
affected:
  - firefox < 128.8.0
  - firefox < 136.0
  - thunderbird < 128.8.0
  - 'thunderbird >= 129.0, < 136.0'
patched:
  - firefox 136.0
  - thunderbird 136.0
published: '2025-03-04'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T19:10:01.007'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-1936'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1940027'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-14/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2025-16/'
    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: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00447
epssPercentile: 0.36484
ingestedAt: '2026-09-30T19:21:07.228Z'
---

## Overview

jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

## Affected

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

## Remediation

Upgrade past the affected range:

- `firefox 136.0`
- `thunderbird 136.0`