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CVE-2016-8635· NVD / CVE Program· CNA redhat

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

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.

MediumCVSS 5.9 · v3.0—No exploit Fix available
Published
Aug 1, 2018
Updated
Jun 16, 2026
EPSS
2.0% · 80th percentile
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Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.0%

CNA vs NVD score

NVD
5.9
CNA · redhat
5.3
0.6 point gap

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
mozillanetwork security services
redhatenterprise linux desktop
redhatenterprise linux server
redhatenterprise linux server aus
redhatenterprise linux server eus
redhatenterprise linux server tus
redhatenterprise linux workstation

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • mozilla network security services3.21 and later · up to 3.21.4 inclusive
  • redhat enterprise linux desktop5.0
  • redhat enterprise linux desktop6.0
  • redhat enterprise linux desktop7.0
  • redhat enterprise linux server5.0
  • redhat enterprise linux server6.0
  • redhat enterprise linux server7.0
  • redhat enterprise linux server aus7.3
  • redhat enterprise linux server aus7.4
  • redhat enterprise linux server aus7.6
  • redhat enterprise linux server eus7.3
  • redhat enterprise linux server eus7.4
  • redhat enterprise linux server eus7.5
  • redhat enterprise linux server eus7.6
  • redhat enterprise linux server tus7.3
  • redhat enterprise linux server tus7.6
  • redhat enterprise linux workstation5.0
  • redhat enterprise linux workstation6.0
  • redhat enterprise linux workstation7.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Mozilla nss

    • 3.21.xaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12nssbefore 2:3.25-12:3.25-1
Red Hat:enterprise_linux:5::clientnssbefore 0:3.21.3-2.el5_110:3.21.3-2.el5_11
Red Hat:enterprise_linux:5::clientnss-debuginfobefore 0:3.21.3-2.el5_110:3.21.3-2.el5_11
Red Hat:enterprise_linux:5::clientnss-toolsbefore 0:3.21.3-2.el5_110:3.21.3-2.el5_11
Red Hat:enterprise_linux:5::client_workstationnss-develbefore 0:3.21.3-2.el5_110:3.21.3-2.el5_11
Red Hat:enterprise_linux:5::client_workstationnss-pkcs11-develbefore 0:3.21.3-2.el5_110:3.21.3-2.el5_11
Red Hat:enterprise_linux:6::clientnssbefore 0:3.21.3-2.el6_80:3.21.3-2.el6_8
Red Hat:enterprise_linux:6::clientnss-debuginfobefore 0:3.21.3-2.el6_80:3.21.3-2.el6_8
Red Hat:enterprise_linux:6::clientnss-develbefore 0:3.21.3-2.el6_80:3.21.3-2.el6_8
Red Hat:enterprise_linux:6::clientnss-pkcs11-develbefore 0:3.21.3-2.el6_80:3.21.3-2.el6_8
Red Hat:enterprise_linux:6::clientnss-sysinitbefore 0:3.21.3-2.el6_80:3.21.3-2.el6_8
Red Hat:enterprise_linux:6::clientnss-toolsbefore 0:3.21.3-2.el6_80:3.21.3-2.el6_8
Red Hat:enterprise_linux:6::clientnss-utilbefore 0:3.21.3-1.el6_80:3.21.3-1.el6_8
Red Hat:enterprise_linux:6::clientnss-util-debuginfobefore 0:3.21.3-1.el6_80:3.21.3-1.el6_8
Red Hat:enterprise_linux:6::clientnss-util-develbefore 0:3.21.3-1.el6_80:3.21.3-1.el6_8
Red Hat:enterprise_linux:7::clientnssbefore 0:3.21.3-2.el7_30:3.21.3-2.el7_3
Red Hat:enterprise_linux:7::clientnss-debuginfobefore 0:3.21.3-2.el7_30:3.21.3-2.el7_3
Red Hat:enterprise_linux:7::clientnss-develbefore 0:3.21.3-2.el7_30:3.21.3-2.el7_3
Red Hat:enterprise_linux:7::clientnss-pkcs11-develbefore 0:3.21.3-2.el7_30:3.21.3-2.el7_3
Red Hat:enterprise_linux:7::clientnss-sysinitbefore 0:3.21.3-2.el7_30:3.21.3-2.el7_3
Red Hat:enterprise_linux:7::clientnss-toolsbefore 0:3.21.3-2.el7_30:3.21.3-2.el7_3
Red Hat:enterprise_linux:7::clientnss-utilbefore 0:3.21.3-1.1.el7_30:3.21.3-1.1.el7_3
Red Hat:enterprise_linux:7::clientnss-util-debuginfobefore 0:3.21.3-1.1.el7_30:3.21.3-1.1.el7_3
Red Hat:enterprise_linux:7::clientnss-util-develbefore 0:3.21.3-1.1.el7_30:3.21.3-1.1.el7_3

+7

Same product

mozilla: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-5461Mozilla Network Security Services (NSS) before 3.21.4, 3.22.x through 3.28.x before 3.28.4, 3.29.x before 3.29.5, and 3.30.x before 3.30.1 a
    40Plan
  • CVE-2009-2404Heap-based buffer overflow in a regular-expression parser in Mozilla Network Security Services (NSS) before 3.12.3, as used in Firefox, Thun
    38Monitor
  • CVE-2018-12404A cached side channel attack during handshakes using RSA encryption could allow for the decryption of encrypted content.
    36Monitor
  • CVE-2016-2834Mozilla Network Security Services (NSS) before 3.23, as used in Mozilla Firefox before 47.0, allows remote attackers to cause a denial of se
    36Monitor
  • CVE-2016-1950Heap-based buffer overflow in Mozilla Network Security Services (NSS) before 3.19.2.3 and 3.20.x and 3.21.x before 3.21.1, as used in Mozill
    36Monitor
  • CVE-2015-7181The sec_asn1d_parse_leaf function in Mozilla Network Security Services (NSS) before 3.19.2.1 and 3.20.x before 3.20.1, as used in Firefox be
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:nss2:3.25-1 · Debian:12Package registry (OSV)
red hat:nss0:3.21.3-2.el5_11 · Red Hat:enterprise_linux:5::clientPackage registry (OSV)
red hat:nss-debuginfo0:3.21.3-2.el5_11 · Red Hat:enterprise_linux:5::clientPackage registry (OSV)
red hat:nss-devel0:3.21.3-2.el5_11 · Red Hat:enterprise_linux:5::client_workstationPackage registry (OSV)
red hat:nss-pkcs11-devel0:3.21.3-2.el5_11 · Red Hat:enterprise_linux:5::client_workstationPackage registry (OSV)
red hat:nss-sysinit0:3.21.3-2.el6_8 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:nss-tools0:3.21.3-2.el5_11 · Red Hat:enterprise_linux:5::clientPackage registry (OSV)
red hat:nss-util0:3.21.3-1.el6_8 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:nss-util-debuginfo0:3.21.3-1.el6_8 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:nss-util-devel0:3.21.3-1.el6_8 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
suse:java-1_8_0-openjdk1.8.0.121-23.4 · SUSE:Linux Enterprise Desktop 12 SP1Package registry (OSV)
suse:mozilla-nspr4.13.1-32.1 · SUSE:Linux Enterprise Software Development Kit 11 SP4Package registry (OSV)
suse:mozilla-nss3.29.5-46.1 · SUSE:Linux Enterprise Software Development Kit 11 SP4Package registry (OSV)
suse:MozillaFirefox45.9.0esr-71.2 · SUSE:Linux Enterprise Software Development Kit 11 SP4Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-358 · Improperly Implemented Security Check for Standard

CVSS vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records