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Fencer Vulns
medium 5.9

CVE-2018-12384 json

When handling a SSLv2-compatible ClientHello request, the server doesn't generate a new random value but sends an all-zero value instead.

published 2019-04-29 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4358

cvss
5.9
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

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.

Patch / fix

  • mozilla network_security_services 3.39
  • nss Debian 14, Debian 13, Debian 12 2:3.39-1

debian advisories DEBIAN-CVE-2018-12384

  • nss Ubuntu 14.04 LTS 2:3.28.4-0ubuntu0.14.04.4
  • nss Ubuntu 16.04 LTS 2:3.28.4-0ubuntu0.16.04.4
  • nss Ubuntu 18.04 LTS 2:3.35-2ubuntu2.1

ubuntu advisories UBUNTU-CVE-2018-12384

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • nss RHEL 7 3.36.0-7.el7_5
  • nss-tools RHEL 7 3.36.0-7.el7_5
  • nss-sysinit RHEL 7 3.36.0-7.el7_5
  • nss RHEL 6 3.36.0-9.el6_10
  • nss-tools RHEL 6 3.36.0-9.el6_10
  • nss-sysinit RHEL 6 3.36.0-9.el6_10

red hat advisories RHSA-2018:2768RHSA-2018:2898

  • mozilla-nss SLES 12 SP4, SLES 12 SP3, SLES 12 SP2-BCL +13 more 3.40.1-58.18.1
  • mozilla-nspr SLES 12 SP4, SLES 12 SP3, SLES 12 SP2-BCL +13 more 4.20-19.6.1
  • MozillaFirefox SLES 12 SP4, SLES 12 SP3, SLES 12 SP2-BCL +13 more 60.4.0esr-109.55.1
  • mozilla-nss SLE Module for Basesystem 15 3.40.1-3.7.2
  • mozilla-nspr SLE Module for Basesystem 15 4.20-3.3.2
  • MozillaFirefox SLE Module for Desktop Applications 15 60.4.0-3.21.1

suse advisories SUSE-SU-2018:4236-2SUSE-SU-2018:4236-1SUSE-SU-2018:4235-1

  • mozilla-nss openSUSE Tumbleweed 3.69.1-1.2

opensuse advisories openSUSE-SU-2024:11058-1

  • nss Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 3.39-r0
  • nss Alpine 3.8 3.36.1-r1

alpine advisories ALPINE-CVE-2018-12384

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-12384 updated cvss 4.8

nss: ServerHello.random is all zeros when handling a v2-compatible ClientHello

  • Red Hat Enterprise Linux Client (v. 7) nss 3.36.0-7.el7_5, nss-tools 3.36.0-7.el7_5, nss-sysinit 3.36.0-7.el7_5 Red Hat Enterprise Linux Client Optional (v. 7) nss-devel 3.36.0-7.el7_5, nss-debuginfo 3.36.0-7.el7_5, nss-pkcs11-devel 3.36.0-7.el7_5 Red Hat Enterprise Linux ComputeNode (v. 7) nss 3.36.0-7.el7_5, nss-tools 3.36.0-7.el7_5, nss-sysinit 3.36.0-7.el7_5 Red Hat Enterprise Linux ComputeNode Optional (v. 7) nss-devel 3.36.0-7.el7_5, nss-debuginfo 3.36.0-7.el7_5, nss-pkcs11-devel 3.36.0-7.el7_5
    fixed: vendor fix RHSA-2018:2768
  • Red Hat Enterprise Linux Desktop (v. 6) nss 3.36.0-9.el6_10, nss-tools 3.36.0-9.el6_10, nss-sysinit 3.36.0-9.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) nss-devel 3.36.0-9.el6_10, nss-debuginfo 3.36.0-9.el6_10, nss-pkcs11-devel 3.36.0-9.el6_10
    fixed: vendor fix RHSA-2018:2898
  • Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) nss 3.36.0-7.el7_5, nss-tools 3.36.0-7.el7_5, nss-sysinit 3.36.0-7.el7_5 Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) nss-debuginfo 3.36.0-7.el7_5, nss-pkcs11-devel 3.36.0-7.el7_5
    fixed: vendor fix RHSA-2018:2768
  • Red Hat Enterprise Linux HPC Node (v. 6) nss 3.36.0-9.el6_10, nss-tools 3.36.0-9.el6_10, nss-sysinit 3.36.0-9.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) nss-devel 3.36.0-9.el6_10, nss-debuginfo 3.36.0-9.el6_10, nss-pkcs11-devel 3.36.0-9.el6_10 Red Hat Enterprise Linux Server (v. 6) nss 3.36.0-9.el6_10, nss-tools 3.36.0-9.el6_10, nss-sysinit 3.36.0-9.el6_10
    fixed: vendor fix RHSA-2018:2898
  • Red Hat Enterprise Linux Server (v. 7) nss 3.36.0-7.el7_5, nss-tools 3.36.0-7.el7_5, nss-sysinit 3.36.0-7.el7_5
    fixed: vendor fix RHSA-2018:2768
  • Red Hat Enterprise Linux Server Optional (v. 6) nss-debuginfo 3.36.0-9.el6_10, nss-pkcs11-devel 3.36.0-9.el6_10
    fixed: vendor fix RHSA-2018:2898
  • Red Hat Enterprise Linux Server Optional (v. 7) nss-debuginfo 3.36.0-7.el7_5, nss-pkcs11-devel 3.36.0-7.el7_5
    fixed: vendor fix RHSA-2018:2768
  • Red Hat Enterprise Linux Workstation (v. 6) nss 3.36.0-9.el6_10, nss-tools 3.36.0-9.el6_10, nss-sysinit 3.36.0-9.el6_10
    fixed: vendor fix RHSA-2018:2898
show 4 more
  • Red Hat Enterprise Linux Workstation (v. 7) nss 3.36.0-7.el7_5, nss-tools 3.36.0-7.el7_5, nss-sysinit 3.36.0-7.el7_5
    fixed: vendor fix RHSA-2018:2768
  • Red Hat Enterprise Linux Workstation Optional (v. 6) nss-debuginfo 3.36.0-9.el6_10, nss-pkcs11-devel 3.36.0-9.el6_10
    fixed: vendor fix RHSA-2018:2898
  • Red Hat Enterprise Linux Workstation Optional (v. 7) nss-debuginfo 3.36.0-7.el7_5, nss-pkcs11-devel 3.36.0-7.el7_5
    fixed: vendor fix RHSA-2018:2768
  • Red Hat Enterprise Linux 5 nss Red Hat Enterprise Linux 8 nss, nss-util, nss-tools, nss-softokn, nss-sysinit, nss-softokn-freebl
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.48% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Affected products

  • NSS Network Security Services (NSS)

Classification

Weakness
  • CWE-335 Incorrect Usage of Seeds in Pseudo-Random Number Generator (PRNG)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.