CVE-2021-43542

Publication date 8 December 2021

Last updated 25 August 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

Description

Using XMLHttpRequest, an attacker could have identified installed applications by probing error messages for loading external protocols. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

Read the notes from the security team

Status

Package Ubuntu Release Status
firefox 24.04 LTS noble
Fixed 95.0+build1-0ubuntu1
23.10 mantic
Fixed 95.0+build1-0ubuntu1
23.04 lunar
Fixed 95.0+build1-0ubuntu1
22.10 kinetic
Fixed 95.0+build1-0ubuntu1
22.04 LTS jammy
Fixed 95.0+build1-0ubuntu1
21.10 impish
Fixed 95.0+build1-0ubuntu0.21.10.1
21.04 hirsute
Fixed 95.0+build1-0ubuntu0.21.04.1
20.04 LTS focal
Fixed 95.0+build1-0ubuntu0.20.04.1
18.04 LTS bionic
Fixed 95.0+build1-0ubuntu0.18.04.1
16.04 LTS xenial Ignored end of standard support, was needed
14.04 LTS trusty Not in release
firefox-esr 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored end of standard support
14.04 LTS trusty Ignored end of standard support
mozjs38 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
mozjs52 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Ignored
18.04 LTS bionic Ignored
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
mozjs68 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Ignored
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
mozjs78 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Ignored end of life, was needs-triage
22.10 kinetic Ignored end of life, was needs-triage
22.04 LTS jammy Ignored
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
thunderbird 24.04 LTS noble
Fixed 1:91.4.0+build1-0ubuntu1
23.10 mantic
Fixed 1:91.4.0+build1-0ubuntu1
23.04 lunar
Fixed 1:91.4.0+build1-0ubuntu1
22.10 kinetic
Fixed 1:91.4.0+build1-0ubuntu1
22.04 LTS jammy
Fixed 1:91.4.0+build1-0ubuntu1
21.10 impish
Fixed 1:91.5.0+build1-0ubuntu0.21.10.1
21.04 hirsute Ignored end of life
20.04 LTS focal
Fixed 1:91.5.0+build1-0ubuntu0.20.04.1
18.04 LTS bionic
Fixed 1:91.5.0+build1-0ubuntu0.18.04.1
16.04 LTS xenial Ignored end of standard support, was needed
14.04 LTS trusty Not in release

Notes

tyhicks

mozjs contains a copy of the SpiderMonkey JavaScript engine

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Scope Unchanged
Confidentiality High
Integrity impact None
Availability impact None
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

References

Related Ubuntu Security Notices (USN)

    • USN-5186-1
    • Firefox vulnerabilities
    • 9 December 2021
    • USN-5246-1
    • Thunderbird vulnerabilities
    • 21 January 2022
    • USN-5248-1
    • Thunderbird vulnerabilities
    • 21 January 2022

Other references