CVE-2020-12387
Firefox ESR: A race condition when running shutdown code for Web Worker led to a use-after-free vulnerability.
CVE-2020-12387 is fixed in 10 products on 2 platforms, first by RHSA-2020:2031, released May 6, 2020. It is not reported as exploited. Patch Radar priority: Urgent.
UrgentFixed on 2 platforms
CVSS
8.8
Critical
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0144
73rd percentile
A race condition when running shutdown code for Web Worker led to a use-after-free vulnerability. This resulted in a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.8, Firefox < 76, and Thunderbird < 68.8.0.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Mozilla Firefox ESR (en-US) | 78.0esr | Mozilla Firefox ESR (en-US) 78.0esr | Jun 25, 2020 |
| Linux | |||
| firefox · RHEL 8 | 0:68.8.0-1.el8_2 | RHSA-2020:2031 | May 6, 2020 |
| firefox · Ubuntu 18.04.6 LTS (bionic) | 76.0+build2-0ubuntu0.18.04.1 | firefox 76.0+build2-0ubuntu0.18.04.1 | May 6, 2020 |
| firefox · Ubuntu 20.04 LTS (focal) | 76.0+build2-0ubuntu0.20.04.1 | firefox 76.0+build2-0ubuntu0.20.04.1 | May 6, 2020 |
| firefox · ol 8 | 0:68.8.0-1.0.1.el8_2 | ELSA-2020-2031 | May 9, 2020 |
| firefox-geckodriver · Ubuntu 18.04.6 LTS (bionic) | 76.0+build2-0ubuntu0.18.04.1 | firefox-geckodriver 76.0+build2-0ubuntu0.18.04.1 | May 6, 2020 |
| firefox-geckodriver · Ubuntu 20.04 LTS (focal) | 76.0+build2-0ubuntu0.20.04.1 | firefox-geckodriver 76.0+build2-0ubuntu0.20.04.1 | May 6, 2020 |
| firefox-mozsymbols · Ubuntu 18.04.6 LTS (bionic) | 76.0+build2-0ubuntu0.18.04.1 | firefox-mozsymbols 76.0+build2-0ubuntu0.18.04.1 | May 6, 2020 |
| firefox-mozsymbols · Ubuntu 20.04 LTS (focal) | 76.0+build2-0ubuntu0.20.04.1 | firefox-mozsymbols 76.0+build2-0ubuntu0.20.04.1 | May 6, 2020 |
| thunderbird · RHEL 8 | 0:68.8.0-1.el8_2 | RHSA-2020:2046 | May 11, 2020 |
| thunderbird · Ubuntu 18.04.6 LTS (bionic) | 1:68.8.0+build2-0ubuntu0.18.04.2 | thunderbird 1:68.8.0+build2-0ubuntu0.18.04.2 | May 6, 2020 |
| thunderbird · Ubuntu 20.04 LTS (focal) | 1:68.8.0+build2-0ubuntu0.20.04.2 | thunderbird 1:68.8.0+build2-0ubuntu0.20.04.2 | May 6, 2020 |
| thunderbird · ol 8 | 0:68.8.0-1.0.1.el8_2 | ELSA-2020-2046 | May 12, 2020 |
| thunderbird-gnome-support · Ubuntu 18.04.6 LTS (bionic) | 1:68.8.0+build2-0ubuntu0.18.04.2 | thunderbird-gnome-support 1:68.8.0+build2-0ubuntu0.18.04.2 | May 6, 2020 |
| thunderbird-gnome-support · Ubuntu 20.04 LTS (focal) | 1:68.8.0+build2-0ubuntu0.20.04.2 | thunderbird-gnome-support 1:68.8.0+build2-0ubuntu0.20.04.2 | May 6, 2020 |
| thunderbird-mozsymbols · Ubuntu 18.04.6 LTS (bionic) | 1:68.8.0+build2-0ubuntu0.18.04.2 | thunderbird-mozsymbols 1:68.8.0+build2-0ubuntu0.18.04.2 | May 6, 2020 |
| thunderbird-mozsymbols · Ubuntu 20.04 LTS (focal) | 1:68.8.0+build2-0ubuntu0.20.04.2 | thunderbird-mozsymbols 1:68.8.0+build2-0ubuntu0.20.04.2 | May 6, 2020 |
| xul-ext-calendar-timezones · Ubuntu 18.04.6 LTS (bionic) | 1:68.8.0+build2-0ubuntu0.18.04.2 | xul-ext-calendar-timezones 1:68.8.0+build2-0ubuntu0.18.04.2 | May 6, 2020 |
| xul-ext-calendar-timezones · Ubuntu 20.04 LTS (focal) | 1:68.8.0+build2-0ubuntu0.20.04.2 | xul-ext-calendar-timezones 1:68.8.0+build2-0ubuntu0.20.04.2 | May 6, 2020 |
| xul-ext-gdata-provider · Ubuntu 18.04.6 LTS (bionic) | 1:68.8.0+build2-0ubuntu0.18.04.2 | xul-ext-gdata-provider 1:68.8.0+build2-0ubuntu0.18.04.2 | May 6, 2020 |
| xul-ext-gdata-provider · Ubuntu 20.04 LTS (focal) | 1:68.8.0+build2-0ubuntu0.20.04.2 | xul-ext-gdata-provider 1:68.8.0+build2-0ubuntu0.20.04.2 | May 6, 2020 |
| xul-ext-lightning · Ubuntu 18.04.6 LTS (bionic) | 1:68.8.0+build2-0ubuntu0.18.04.2 | xul-ext-lightning 1:68.8.0+build2-0ubuntu0.18.04.2 | May 6, 2020 |
| xul-ext-lightning · Ubuntu 20.04 LTS (focal) | 1:68.8.0+build2-0ubuntu0.20.04.2 | xul-ext-lightning 1:68.8.0+build2-0ubuntu0.20.04.2 | May 6, 2020 |
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