CVE-2018-12384: Mozilla Network Security Services

Medium severity, CVSS 5.9. EPSS: 1.5% chance of exploitation in the next 30 days.

When handling a SSLv2-compatible ClientHello request, the server doesn't generate a new random value but sends an all-zero value instead. This results in full malleability of the ClientHello for SSLv2 used for TLS 1.2 in all versions prior to NSS 3.39. This does not impact TLS 1.3.

Affected products

• Mozilla Network Security Services: before 3.39 (fixed in 3.39)

Published 2019-04-29. Last modified 2026-06-17.