CVE-2018-12384

Severity: medium (CVSS 5.9 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-04-29 · updated 2026-06-17
Weakness: CWE-335

Description

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

How to fix

Upgrade to a fixed version: Mozilla Network Security Services 3.39. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2018-12384
https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2018-12384
https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html

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