CVE-2020-12399: Debian Linux

Medium severity, CVSS 4.4. EPSS: 0.7% chance of exploitation in the next 30 days.

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.

Affected products

• Debian Debian Linux: version 9.0 only
• Mozilla Firefox: before 77.0 (fixed in 77.0)
• Mozilla Firefox ESR: before 68.9.0 (fixed in 68.9.0)
• Mozilla Thunderbird: before 68.9.0 (fixed in 68.9.0)

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