# CVE-2020-12399: Firefox ESR: NSS has shown timing differences when performing DSA signatures, which was exploitable and could eventually… CVE-2020-12399 is fixed in 24 products on 2 platforms, first by libnss3 2:3.35-2ubuntu2.8, released May 25, 2020. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2020-12399 - Priority: Routine - CVSS: 4.4 (Moderate) - EPSS: 0.0065 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: May 25, 2020 - Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-12399 ## Description NSS has shown timing differences when performing DSA signatures, which was exploitable and could eventually leak private keys. This vulnerability affects Thunderbird < 68.9.0, Firefox < 77, and Firefox ESR < 68.9. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Windows apps | Mozilla Firefox ESR (en-US) | 78.0esr | [Mozilla Firefox ESR (en-US) 78.0esr](https://patchblox.com/security/data/fix/windows-app/mozilla.firefox.esr-78.0esr.md) | Jun 25, 2020 | | Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 77.0.1+build1-0ubuntu0.18.04.1 | [firefox 77.0.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-77.0.1-build1-0ubuntu0.18.04.1.md) | Jun 2, 2020 | | Linux | firefox Ubuntu 20.04 LTS (focal) | 77.0.1+build1-0ubuntu0.20.04.1 | [firefox 77.0.1+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-77.0.1-build1-0ubuntu0.20.04.1.md) | Jun 2, 2020 | | Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 77.0.1+build1-0ubuntu0.18.04.1 | [firefox-geckodriver 77.0.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-77.0.1-build1-0ubuntu0.18.04.1.md) | Jun 2, 2020 | | Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 77.0.1+build1-0ubuntu0.20.04.1 | [firefox-geckodriver 77.0.1+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-77.0.1-build1-0ubuntu0.20.04.1.md) | Jun 2, 2020 | | Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 77.0.1+build1-0ubuntu0.18.04.1 | [firefox-mozsymbols 77.0.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-77.0.1-build1-0ubuntu0.18.04.1.md) | Jun 2, 2020 | | Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 77.0.1+build1-0ubuntu0.20.04.1 | [firefox-mozsymbols 77.0.1+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-77.0.1-build1-0ubuntu0.20.04.1.md) | Jun 2, 2020 | | Linux | libnss3 Ubuntu 18.04.6 LTS (bionic) | 2:3.35-2ubuntu2.8 | [libnss3 2:3.35-2ubuntu2.8](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnss3-2-3.35-2ubuntu2.8.md) | May 25, 2020 | | Linux | libnss3 Ubuntu 20.04 LTS (focal) | 2:3.49.1-1ubuntu1.1 | [libnss3 2:3.49.1-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss3-2-3.49.1-1ubuntu1.1.md) | May 25, 2020 | | Linux | libnss3-tools Ubuntu 18.04.6 LTS (bionic) | 2:3.35-2ubuntu2.8 | [libnss3-tools 2:3.35-2ubuntu2.8](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnss3-tools-2-3.35-2ubuntu2.8.md) | May 25, 2020 | | Linux | libnss3-tools Ubuntu 20.04 LTS (focal) | 2:3.49.1-1ubuntu1.1 | [libnss3-tools 2:3.49.1-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss3-tools-2-3.49.1-1ubuntu1.1.md) | May 25, 2020 | | Linux | nspr RHEL 8 | 0:4.25.0-2.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nspr-devel RHEL 8 | 0:4.25.0-2.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn-freebl RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn-freebl-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-sysinit RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-tools RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-util RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-util-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | thunderbird Ubuntu 18.04.6 LTS (bionic) | 1:68.10.0+build1-0ubuntu0.18.04.1 | [thunderbird 1:68.10.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-1-68.10.0-build1-0ubuntu0.18.04.1.md) | Oct 8, 2020 | | Linux | thunderbird Ubuntu 20.04 LTS (focal) | 1:68.10.0+build1-0ubuntu0.20.04.1 | [thunderbird 1:68.10.0+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-1-68.10.0-build1-0ubuntu0.20.04.1.md) | Oct 8, 2020 | | Linux | thunderbird-gnome-support Ubuntu 18.04.6 LTS (bionic) | 1:68.10.0+build1-0ubuntu0.18.04.1 | [thunderbird-gnome-support 1:68.10.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-68.10.0-build1-0ubuntu0.18.04.1.md) | Oct 8, 2020 | | Linux | thunderbird-gnome-support Ubuntu 20.04 LTS (focal) | 1:68.10.0+build1-0ubuntu0.20.04.1 | [thunderbird-gnome-support 1:68.10.0+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-gnome-support-1-68.10.0-build1-0ubuntu0.20.04.1.md) | Oct 8, 2020 | | Linux | thunderbird-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 1:68.10.0+build1-0ubuntu0.18.04.1 | [thunderbird-mozsymbols 1:68.10.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-68.10.0-build1-0ubuntu0.18.04.1.md) | Oct 8, 2020 | | Linux | thunderbird-mozsymbols Ubuntu 20.04 LTS (focal) | 1:68.10.0+build1-0ubuntu0.20.04.1 | [thunderbird-mozsymbols 1:68.10.0+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-mozsymbols-1-68.10.0-build1-0ubuntu0.20.04.1.md) | Oct 8, 2020 | | Linux | xul-ext-calendar-timezones Ubuntu 18.04.6 LTS (bionic) | 1:68.10.0+build1-0ubuntu0.18.04.1 | [xul-ext-calendar-timezones 1:68.10.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-68.10.0-build1-0ubuntu0.18.04.1.md) | Oct 8, 2020 | | Linux | xul-ext-calendar-timezones Ubuntu 20.04 LTS (focal) | 1:68.10.0+build1-0ubuntu0.20.04.1 | [xul-ext-calendar-timezones 1:68.10.0+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-calendar-timezones-1-68.10.0-build1-0ubuntu0.20.04.1.md) | Oct 8, 2020 | | Linux | xul-ext-gdata-provider Ubuntu 18.04.6 LTS (bionic) | 1:68.10.0+build1-0ubuntu0.18.04.1 | [xul-ext-gdata-provider 1:68.10.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-68.10.0-build1-0ubuntu0.18.04.1.md) | Oct 8, 2020 | | Linux | xul-ext-gdata-provider Ubuntu 20.04 LTS (focal) | 1:68.10.0+build1-0ubuntu0.20.04.1 | [xul-ext-gdata-provider 1:68.10.0+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-gdata-provider-1-68.10.0-build1-0ubuntu0.20.04.1.md) | Oct 8, 2020 | | Linux | xul-ext-lightning Ubuntu 18.04.6 LTS (bionic) | 1:68.10.0+build1-0ubuntu0.18.04.1 | [xul-ext-lightning 1:68.10.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-lightning-1-68.10.0-build1-0ubuntu0.18.04.1.md) | Oct 8, 2020 | | Linux | xul-ext-lightning Ubuntu 20.04 LTS (focal) | 1:68.10.0+build1-0ubuntu0.20.04.1 | [xul-ext-lightning 1:68.10.0+build1-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-lightning-1-68.10.0-build1-0ubuntu0.20.04.1.md) | Oct 8, 2020 | --- Data as of 2026-11-08T06:59:42Z UTC. 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