CVE-2020-12402: Debian Linux

Medium severity, CVSS 4.4. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 32 only
• Mozilla Firefox: before 78.0 (fixed in 78.0)
• Opensuse Leap: version 15.1 only; version 15.2 only

Published 2020-07-09. Last modified 2026-06-17.