CVE-2021-43538
Mozilla Firefox ESR and 3 others: By misusing a race in our notification code, an attacker could have forcefully hidden the notification…
CVE-2021-43538 is fixed in 12 products on 2 platforms, first by Mozilla Thunderbird (en-US) 91.4.0, released December 3, 2021. It is not reported as exploited. Patch Radar priority: High.
HighFixed on 2 platforms
CVSS
9.8
Important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0125
69th percentile
By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received full screen and pointer lock access, which could have been used for spoofing attacks. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Mozilla Firefox ESR (en-US) | 102.0 | Mozilla Firefox ESR (en-US) 102.0 | Jun 23, 2022 |
| Mozilla Thunderbird (en-US) | 91.4.0 | Mozilla Thunderbird (en-US) 91.4.0 | Dec 3, 2021 |
| Linux | |||
| firefox · RHEL 8 | 0:91.4.0-1.el8_5 | RHSA-2021:5013 | Dec 8, 2021 |
| firefox · Ubuntu 18.04.6 LTS (bionic) | 95.0+build1-0ubuntu0.18.04.1 | firefox 95.0+build1-0ubuntu0.18.04.1 | Dec 7, 2021 |
| firefox · Ubuntu 20.04 LTS (focal) | 95.0+build1-0ubuntu0.20.04.1 | firefox 95.0+build1-0ubuntu0.20.04.1 | Dec 7, 2021 |
| firefox · Ubuntu 22.04.1 LTS (jammy) | 95.0+build1-0ubuntu1 | firefox 95.0+build1-0ubuntu1 | Dec 7, 2021 |
| firefox · almalinux 8 | 91.4.0-1.el8_5.alma | ALSA-2021:5013 | Dec 8, 2021 |
| firefox · ol 8 | 0:91.4.0-1.0.1.el8_5 | ELSA-2021-5013 | Dec 9, 2021 |
| firefox · rocky 8 | 0:91.4.0-1.el8_5 | RLSA-2021:5013 | Dec 8, 2021 |
| firefox-esr · Debian 12.15 (bookworm) | 91.4.0esr-1 | DEBIAN-CVE-2021-43538 | Dec 8, 2021 |
| firefox-esr · Debian 13.5 (trixie) | 91.4.0esr-1 | DEBIAN-CVE-2021-43538 | Dec 8, 2021 |
| firefox-esr · Debian 14 | 91.4.0esr-1 | DEBIAN-CVE-2021-43538 | Dec 8, 2021 |
| firefox-geckodriver · Ubuntu 18.04.6 LTS (bionic) | 95.0+build1-0ubuntu0.18.04.1 | firefox-geckodriver 95.0+build1-0ubuntu0.18.04.1 | Dec 7, 2021 |
| firefox-geckodriver · Ubuntu 20.04 LTS (focal) | 95.0+build1-0ubuntu0.20.04.1 | firefox-geckodriver 95.0+build1-0ubuntu0.20.04.1 | Dec 7, 2021 |
| firefox-geckodriver · Ubuntu 22.04.1 LTS (jammy) | 95.0+build1-0ubuntu1 | firefox-geckodriver 95.0+build1-0ubuntu1 | Dec 7, 2021 |
| firefox-mozsymbols · Ubuntu 18.04.6 LTS (bionic) | 95.0+build1-0ubuntu0.18.04.1 | firefox-mozsymbols 95.0+build1-0ubuntu0.18.04.1 | Dec 7, 2021 |
| firefox-mozsymbols · Ubuntu 20.04 LTS (focal) | 95.0+build1-0ubuntu0.20.04.1 | firefox-mozsymbols 95.0+build1-0ubuntu0.20.04.1 | Dec 7, 2021 |
| firefox-mozsymbols · Ubuntu 22.04.1 LTS (jammy) | 95.0+build1-0ubuntu1 | firefox-mozsymbols 95.0+build1-0ubuntu1 | Dec 7, 2021 |
| thunderbird · Debian 12.15 (bookworm) | 1:91.4.0-1 | DEBIAN-CVE-2021-43538 | Dec 8, 2021 |
| thunderbird · Debian 13.5 (trixie) | 1:91.4.0-1 | DEBIAN-CVE-2021-43538 | Dec 8, 2021 |
| thunderbird · Debian 14 | 1:91.4.0-1 | DEBIAN-CVE-2021-43538 | Dec 8, 2021 |
| thunderbird · RHEL 8 | 0:91.4.0-2.el8_5 | RHSA-2021:5045 | Dec 9, 2021 |
| thunderbird · Ubuntu 18.04.6 LTS (bionic) | 1:91.5.0+build1-0ubuntu0.18.04.1 | thunderbird 1:91.5.0+build1-0ubuntu0.18.04.1 | Feb 16, 2023 |
| thunderbird · Ubuntu 20.04 LTS (focal) | 1:91.5.0+build1-0ubuntu0.20.04.1 | thunderbird 1:91.5.0+build1-0ubuntu0.20.04.1 | Feb 16, 2023 |
| thunderbird · almalinux 8 | 91.4.0-2.el8_5.alma | ALSA-2021:5045 | Dec 9, 2021 |
| thunderbird · ol 8 | 0:91.4.0-2.0.1.el8_5 | ELSA-2021-5045 | Dec 10, 2021 |
| thunderbird · rocky 8 | 0:91.4.0-2.el8_5 | RLSA-2021:5045 | Dec 9, 2021 |
| thunderbird-gnome-support · Ubuntu 18.04.6 LTS (bionic) | 1:91.5.0+build1-0ubuntu0.18.04.1 | thunderbird-gnome-support 1:91.5.0+build1-0ubuntu0.18.04.1 | Feb 16, 2023 |
| thunderbird-gnome-support · Ubuntu 20.04 LTS (focal) | 1:91.5.0+build1-0ubuntu0.20.04.1 | thunderbird-gnome-support 1:91.5.0+build1-0ubuntu0.20.04.1 | Feb 16, 2023 |
| thunderbird-mozsymbols · Ubuntu 18.04.6 LTS (bionic) | 1:91.5.0+build1-0ubuntu0.18.04.1 | thunderbird-mozsymbols 1:91.5.0+build1-0ubuntu0.18.04.1 | Feb 16, 2023 |
| thunderbird-mozsymbols · Ubuntu 20.04 LTS (focal) | 1:91.5.0+build1-0ubuntu0.20.04.1 | thunderbird-mozsymbols 1:91.5.0+build1-0ubuntu0.20.04.1 | Feb 16, 2023 |
| xul-ext-calendar-timezones · Ubuntu 18.04.6 LTS (bionic) | 1:91.5.0+build1-0ubuntu0.18.04.1 | xul-ext-calendar-timezones 1:91.5.0+build1-0ubuntu0.18.04.1 | Feb 16, 2023 |
| xul-ext-calendar-timezones · Ubuntu 20.04 LTS (focal) | 1:91.5.0+build1-0ubuntu0.20.04.1 | xul-ext-calendar-timezones 1:91.5.0+build1-0ubuntu0.20.04.1 | Feb 16, 2023 |
| xul-ext-gdata-provider · Ubuntu 18.04.6 LTS (bionic) | 1:91.5.0+build1-0ubuntu0.18.04.1 | xul-ext-gdata-provider 1:91.5.0+build1-0ubuntu0.18.04.1 | Feb 16, 2023 |
| xul-ext-gdata-provider · Ubuntu 20.04 LTS (focal) | 1:91.5.0+build1-0ubuntu0.20.04.1 | xul-ext-gdata-provider 1:91.5.0+build1-0ubuntu0.20.04.1 | Feb 16, 2023 |
| xul-ext-lightning · Ubuntu 18.04.6 LTS (bionic) | 1:91.5.0+build1-0ubuntu0.18.04.1 | xul-ext-lightning 1:91.5.0+build1-0ubuntu0.18.04.1 | Feb 16, 2023 |
| xul-ext-lightning · Ubuntu 20.04 LTS (focal) | 1:91.5.0+build1-0ubuntu0.20.04.1 | xul-ext-lightning 1:91.5.0+build1-0ubuntu0.20.04.1 | Feb 16, 2023 |
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