---
id: CVE-2020-15666
title: >-
  When trying to load a non-video in an audio/video context the exact status
  code (200, 302, 404, 500, 412, 403, etc.) was disclosed via the MediaError
  Message
summary: >-
  When trying to load a non-video in an audio/video context the exact status
  code (200, 302, 404, 500, 412, 403, etc.) was disclosed via the MediaError
  Message. This level of information leakage is inconsistent with the
  standardized onerro…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'
cwe:
  - CWE-209
vendor: mozilla
product: firefox
affected:
  - firefox < 80.0
  - firefox_mobile < 80.0
patched:
  - firefox 80.0
  - firefox_mobile 80.0
published: '2020-10-01'
updated: '2026-08-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-15666'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1450853'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-36/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-39/'
    label: security@mozilla.org
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1450853'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-36/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-39/'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01228
epssPercentile: 0.67572
ingestedAt: '2026-08-19T15:41:14.493Z'
---

## Overview

When trying to load a non-video in an audio/video context the exact status code (200, 302, 404, 500, 412, 403, etc.) was disclosed via the MediaError Message. This level of information leakage is inconsistent with the standardized onerror/onsuccess disclosure and can lead to inferring login status to services or device discovery on a local network among other attacks. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

## Affected

- `firefox < 80.0`
- `firefox_mobile < 80.0`

## Remediation

Upgrade past the affected range:

- `firefox 80.0`
- `firefox_mobile 80.0`