CVE-2020-26973
Firefox ESR and 2 others: Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed.
CVE-2020-26973 is fixed in 11 products on 2 platforms, first by firefox 84.0+build3-0ubuntu0.18.04.1, released December 14, 2020. It is not reported as exploited. Patch Radar priority: High.
HighFixed on 2 platforms
CVSS
8.8
Important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0162
76th percentile
Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed. This could have been used as a sanitizer bypass. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Mozilla Firefox ESR (en-US) | 91.0 | Mozilla Firefox ESR (en-US) 91.0 | Aug 4, 2021 |
| Mozilla Thunderbird (en-US) | 78.10.0 | Mozilla Thunderbird (en-US) 78.10.0 | Apr 15, 2021 |
| Linux | |||
| firefox · RHEL 8 | 0:78.6.0-1.el8_3 | RHSA-2020:5562 | Dec 16, 2020 |
| firefox · Ubuntu 18.04.6 LTS (bionic) | 84.0+build3-0ubuntu0.18.04.1 | firefox 84.0+build3-0ubuntu0.18.04.1 | Dec 14, 2020 |
| firefox · Ubuntu 20.04 LTS (focal) | 84.0+build3-0ubuntu0.20.04.1 | firefox 84.0+build3-0ubuntu0.20.04.1 | Dec 14, 2020 |
| firefox · ol 8 | 0:78.6.0-1.0.1.el8_3 | ELSA-2020-5562-1 | Dec 17, 2020 |
| firefox-geckodriver · Ubuntu 18.04.6 LTS (bionic) | 84.0+build3-0ubuntu0.18.04.1 | firefox-geckodriver 84.0+build3-0ubuntu0.18.04.1 | Dec 14, 2020 |
| firefox-geckodriver · Ubuntu 20.04 LTS (focal) | 84.0+build3-0ubuntu0.20.04.1 | firefox-geckodriver 84.0+build3-0ubuntu0.20.04.1 | Dec 14, 2020 |
| firefox-mozsymbols · Ubuntu 18.04.6 LTS (bionic) | 84.0+build3-0ubuntu0.18.04.1 | firefox-mozsymbols 84.0+build3-0ubuntu0.18.04.1 | Dec 14, 2020 |
| firefox-mozsymbols · Ubuntu 20.04 LTS (focal) | 84.0+build3-0ubuntu0.20.04.1 | firefox-mozsymbols 84.0+build3-0ubuntu0.20.04.1 | Dec 14, 2020 |
| thunderbird · RHEL 8 | 0:78.6.0-1.el8_3 | RHSA-2020:5624 | Dec 17, 2020 |
| thunderbird · Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | thunderbird 1:78.8.1+build1-0ubuntu0.18.04.1 | Apr 22, 2021 |
| thunderbird · Ubuntu 20.04 LTS (focal) | 1:78.7.1+build1-0ubuntu0.20.04.1 | thunderbird 1:78.7.1+build1-0ubuntu0.20.04.1 | Jan 25, 2021 |
| thunderbird · ol 8 | 0:78.6.0-1.0.1.el8_3 | ELSA-2020-5624-1 | Dec 18, 2020 |
| thunderbird-gnome-support · Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | thunderbird-gnome-support 1:78.8.1+build1-0ubuntu0.18.04.1 | Apr 22, 2021 |
| thunderbird-gnome-support · Ubuntu 20.04 LTS (focal) | 1:78.7.1+build1-0ubuntu0.20.04.1 | thunderbird-gnome-support 1:78.7.1+build1-0ubuntu0.20.04.1 | Jan 25, 2021 |
| thunderbird-mozsymbols · Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | thunderbird-mozsymbols 1:78.8.1+build1-0ubuntu0.18.04.1 | Apr 22, 2021 |
| thunderbird-mozsymbols · Ubuntu 20.04 LTS (focal) | 1:78.7.1+build1-0ubuntu0.20.04.1 | thunderbird-mozsymbols 1:78.7.1+build1-0ubuntu0.20.04.1 | Jan 25, 2021 |
| xul-ext-calendar-timezones · Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | xul-ext-calendar-timezones 1:78.8.1+build1-0ubuntu0.18.04.1 | Apr 22, 2021 |
| xul-ext-calendar-timezones · Ubuntu 20.04 LTS (focal) | 1:78.7.1+build1-0ubuntu0.20.04.1 | xul-ext-calendar-timezones 1:78.7.1+build1-0ubuntu0.20.04.1 | Jan 25, 2021 |
| xul-ext-gdata-provider · Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | xul-ext-gdata-provider 1:78.8.1+build1-0ubuntu0.18.04.1 | Apr 22, 2021 |
| xul-ext-gdata-provider · Ubuntu 20.04 LTS (focal) | 1:78.7.1+build1-0ubuntu0.20.04.1 | xul-ext-gdata-provider 1:78.7.1+build1-0ubuntu0.20.04.1 | Jan 25, 2021 |
| xul-ext-lightning · Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | xul-ext-lightning 1:78.8.1+build1-0ubuntu0.18.04.1 | Apr 22, 2021 |
| xul-ext-lightning · Ubuntu 20.04 LTS (focal) | 1:78.7.1+build1-0ubuntu0.20.04.1 | xul-ext-lightning 1:78.7.1+build1-0ubuntu0.20.04.1 | Jan 25, 2021 |
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