# CVE-2020-12402: Firefox ESR: During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm… CVE-2020-12402 is fixed in 15 products on 2 platforms, first by libnss3 2:3.35-2ubuntu2.9, released June 18, 2020. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2020-12402 - Priority: Routine - CVSS: 4.4 (Moderate) - EPSS: 0.0034 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 18, 2020 - Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-12402 ## Description During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm which entailed significantly input-dependent flow. This allowed an attacker able to perform electromagnetic-based side channel attacks to record traces leading to the recovery of the secret primes. *Note:* An unmodified Firefox browser does not generate RSA keys in normal operation and is not affected, but products built on top of it might. This vulnerability affects Firefox < 78. ## 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 | libnss3 Ubuntu 18.04.6 LTS (bionic) | 2:3.35-2ubuntu2.9 | [libnss3 2:3.35-2ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnss3-2-3.35-2ubuntu2.9.md) | Jun 18, 2020 | | Linux | libnss3 Ubuntu 20.04 LTS (focal) | 2:3.49.1-1ubuntu1.2 | [libnss3 2:3.49.1-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss3-2-3.49.1-1ubuntu1.2.md) | Jun 18, 2020 | | Linux | libnss3-tools Ubuntu 18.04.6 LTS (bionic) | 2:3.35-2ubuntu2.9 | [libnss3-tools 2:3.35-2ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnss3-tools-2-3.35-2ubuntu2.9.md) | Jun 18, 2020 | | Linux | libnss3-tools Ubuntu 20.04 LTS (focal) | 2:3.49.1-1ubuntu1.2 | [libnss3-tools 2:3.49.1-1ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss3-tools-2-3.49.1-1ubuntu1.2.md) | Jun 18, 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 ol 8 | 0:4.25.0-2.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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 | nspr-devel ol 8 | 0:4.25.0-2.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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 ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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 ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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 ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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-softokn-freebl-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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-sysinit ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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-tools ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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 ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 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 | nss-util-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | --- Data as of 2026-11-08T06:59:42Z UTC. 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