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Fencer Intel
medium 5.3

CVE-2016-8635 json

It was found that Diffie Hellman Client key exchange handling in NSS 3.21.x was vulnerable to small subgroup confinement attack.

published 2018-08-01 8 y ago modified 2026-06-17 4 mo ago also EUVD-2016-9478

cvss
5.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

It was found that Diffie Hellman Client key exchange handling in NSS 3.21.x was vulnerable to small subgroup confinement attack. An attacker could use this flaw to recover private keys by confining the client DH key to small subgroup of the desired group.

Patch / fix

  • nss Debian 14, Debian 13, Debian 12 2:3.25-1

debian advisories DEBIAN-CVE-2016-8635

  • nss Ubuntu 14.04 LTS 2:3.26.2-0ubuntu0.14.04.3
  • nss Ubuntu 16.04 LTS 2:3.26.2-0ubuntu0.16.04.2

ubuntu advisories UBUNTU-CVE-2016-8635

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 5 3.21.3-2.el5_11
  • nss RHEL 6 3.21.3-2.el6_8
  • nss RHEL 7 3.21.3-2.el7_3
  • nss-util RHEL 6 3.21.3-1.el6_8
  • nss-util RHEL 7 3.21.3-1.1.el7_3
  • nss-tools RHEL 5 3.21.3-2.el5_11
  • nss-tools RHEL 6 3.21.3-2.el6_8
  • nss-tools RHEL 7 3.21.3-2.el7_3

red hat advisories RHSA-2016:2779

  • java-1_8_0-openjdk SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for Raspberry Pi 12 SP2 +4 more 1.8.0.121-23.4
  • mozilla-nss SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +8 more 3.29.5-57.1
  • mozilla-nspr SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +8 more 4.13.1-18.1
  • MozillaFirefox SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +8 more 45.9.0esr-105.1
  • mozilla-nspr SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +6 more 4.13.1-32.1
  • mozilla-nss SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +6 more 3.29.5-46.1
  • MozillaFirefox SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +6 more 45.9.0esr-71.2

suse advisories SUSE-SU-2017:1248-1SUSE-SU-2017:1175-1

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-2016-8635 updated cvss 5.3

nss: small-subgroups attack flaw

  • Red Hat Enterprise Linux (v. 5 server) nss 3.21.3-2.el5_11, nss-tools 3.21.3-2.el5_11 Red Hat Enterprise Linux Client (v. 7) nss 3.21.3-2.el7_3, nss-tools 3.21.3-2.el7_3, nss-util 3.21.3-1.1.el7_3, nss-sysinit 3.21.3-2.el7_3 Red Hat Enterprise Linux Client Optional (v. 7) nss-devel 3.21.3-2.el7_3, nss-debuginfo 3.21.3-2.el7_3, nss-pkcs11-devel 3.21.3-2.el7_3, nss-util-devel 3.21.3-1.1.el7_3, nss-util-debuginfo 3.21.3-1.1.el7_3 Red Hat Enterprise Linux ComputeNode (v. 7) nss 3.21.3-2.el7_3, nss-tools 3.21.3-2.el7_3, nss-util 3.21.3-1.1.el7_3, nss-sysinit 3.21.3-2.el7_3 Red Hat Enterprise Linux ComputeNode Optional (v. 7) nss-devel 3.21.3-2.el7_3, nss-debuginfo 3.21.3-2.el7_3, nss-pkcs11-devel 3.21.3-2.el7_3, nss-util-devel 3.21.3-1.1.el7_3, nss-util-debuginfo 3.21.3-1.1.el7_3 Red Hat Enterprise Linux Desktop (v. 5 client) nss 3.21.3-2.el5_11, nss-tools 3.21.3-2.el5_11
    +13 more products
    Red Hat Enterprise Linux Desktop (v. 6) nss 3.21.3-2.el6_8, nss-util 3.21.3-1.el6_8, nss-tools 3.21.3-2.el6_8, nss-sysinit 3.21.3-2.el6_8 Red Hat Enterprise Linux Desktop Optional (v. 6) nss-devel 3.21.3-2.el6_8, nss-debuginfo 3.21.3-2.el6_8, nss-util-devel 3.21.3-1.el6_8, nss-pkcs11-devel 3.21.3-2.el6_8, nss-util-debuginfo 3.21.3-1.el6_8 Red Hat Enterprise Linux Desktop Workstation (v. 5 client) nss 3.21.3-2.el5_11 Red Hat Enterprise Linux HPC Node (v. 6) nss 3.21.3-2.el6_8, nss-util 3.21.3-1.el6_8, nss-tools 3.21.3-2.el6_8, nss-sysinit 3.21.3-2.el6_8 Red Hat Enterprise Linux HPC Node Optional (v. 6) nss-devel 3.21.3-2.el6_8, nss-debuginfo 3.21.3-2.el6_8, nss-util-devel 3.21.3-1.el6_8, nss-pkcs11-devel 3.21.3-2.el6_8, nss-util-debuginfo 3.21.3-1.el6_8 Red Hat Enterprise Linux Server (v. 6) nss 3.21.3-2.el6_8, nss-util 3.21.3-1.el6_8, nss-tools 3.21.3-2.el6_8, nss-sysinit 3.21.3-2.el6_8 Red Hat Enterprise Linux Server (v. 7) nss 3.21.3-2.el7_3, nss-tools 3.21.3-2.el7_3, nss-util 3.21.3-1.1.el7_3, nss-sysinit 3.21.3-2.el7_3 Red Hat Enterprise Linux Server Optional (v. 6) nss-debuginfo 3.21.3-2.el6_8, nss-pkcs11-devel 3.21.3-2.el6_8 Red Hat Enterprise Linux Server Optional (v. 7) nss-debuginfo 3.21.3-2.el7_3, nss-pkcs11-devel 3.21.3-2.el7_3 Red Hat Enterprise Linux Workstation (v. 6) nss 3.21.3-2.el6_8, nss-util 3.21.3-1.el6_8, nss-tools 3.21.3-2.el6_8, nss-sysinit 3.21.3-2.el6_8 Red Hat Enterprise Linux Workstation (v. 7) nss 3.21.3-2.el7_3, nss-tools 3.21.3-2.el7_3, nss-util 3.21.3-1.1.el7_3, nss-sysinit 3.21.3-2.el7_3 Red Hat Enterprise Linux Workstation Optional (v. 6) nss-debuginfo 3.21.3-2.el6_8, nss-pkcs11-devel 3.21.3-2.el6_8 Red Hat Enterprise Linux Workstation Optional (v. 7) nss-debuginfo 3.21.3-2.el7_3, nss-pkcs11-devel 3.21.3-2.el7_3
    fixed: vendor fix RHSA-2016:2779

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

1.99% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
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

  • Mozilla nss

Classification

Weakness
  • CWE-358 Improperly Implemented Security Check for Standard
  • CWE-320 Key Management Errors

References

Sources

Fencer Intel 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.