---
id: CVE-2020-15664
title: >-
  By holding a reference to the eval() function from an about:blank window, a
  malicious webpage could have gained access to the InstallTrigger object which
  would allow them to prompt the user to install an extension
summary: >-
  By holding a reference to the eval() function from an about:blank window, a
  malicious webpage could have gained access to the InstallTrigger object which
  would allow them to prompt the user to install an extension. Combined with
  user con…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N'
cwe:
  - CWE-863
vendor: mozilla
product: firefox
affected:
  - firefox < 80.0
  - 'firefox >= 78.0, < 78.2'
  - firefox_esr < 68.12
  - firefox_mobile < 80.0
  - thunderbird < 68.12
  - 'thunderbird >= 78.0, < 78.2'
patched:
  - firefox 78.2
  - firefox_esr 68.12
  - firefox_mobile 80.0
  - thunderbird 78.2
published: '2020-10-01'
updated: '2026-08-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-15664'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1658214'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-36/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-37/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-38/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-39/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-40/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-41/'
    label: security@mozilla.org
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=1658214'
    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/mfsa2020-37/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-38/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-39/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-40/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.mozilla.org/security/advisories/mfsa2020-41/'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01378
epssPercentile: 0.70878
ingestedAt: '2026-08-19T16:41:54.455Z'
---

## Overview

By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, Firefox ESR < 78.2, and Firefox for Android < 80.

## Affected

- `firefox < 80.0`
- `firefox >= 78.0, < 78.2`
- `firefox_esr < 68.12`
- `firefox_mobile < 80.0`
- `thunderbird < 68.12`
- `thunderbird >= 78.0, < 78.2`

## Remediation

Upgrade past the affected range:

- `firefox 78.2`
- `firefox_esr 68.12`
- `firefox_mobile 80.0`
- `thunderbird 78.2`