OpenSSL: DH small subgroups
Published Feb 15, 2016
3.7
LOWCVSS 3.0
EPSS 83.64%
Description
The DH_check_pub_key function in crypto/dh/dh_check.c in OpenSSL 1.0.2 before 1.0.2f does not ensure that prime numbers are appropriate for Diffie-Hellman (DH) key exchange, which makes it easier for remote attackers to discover a private DH exponent by making multiple handshakes with a peer that chose an inappropriate number, as demonstrated by a number in an X9.42 file.
Affected products
No data.
- 1.0.2
- 1.0.2
- 1.0.2
- 1.0.2
- 1.0.2a
- 1.0.2b
- 1.0.2c
- 1.0.2d
- 1.0.2e
No data.
Red Hat Enterprise Linux 5
openssl
Not affected
Red Hat Enterprise Linux 5
openssl097a
Not affected
Red Hat Enterprise Linux 6
openssl
Not affected
Red Hat Enterprise Linux 6
openssl098e
Not affected
Red Hat Enterprise Linux 7
openssl
Not affected
Red Hat Enterprise Linux 7
openssl098e
Not affected
Red Hat JBoss Enterprise Application Platform 6
openssl
Not affected
Red Hat JBoss Enterprise Web Server 1
openssl
Not affected
Red Hat JBoss Enterprise Web Server 2
openssl
Not affected
Red Hat JBoss Enterprise Web Server 3
openssl
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | openssl | Not affected | n/a |
| Red Hat Enterprise Linux 5 | openssl097a | Not affected | n/a |
| Red Hat Enterprise Linux 6 | openssl | Not affected | n/a |
| Red Hat Enterprise Linux 6 | openssl098e | Not affected | n/a |
| Red Hat Enterprise Linux 7 | openssl | Not affected | n/a |
| Red Hat Enterprise Linux 7 | openssl098e | Not affected | n/a |
| Red Hat JBoss Enterprise Application Platform 6 | openssl | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 1 | openssl | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 2 | openssl | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 3 | openssl | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
OpenSSL 1.0.2 provides support for generating X9.42 style parameter files. This feature does not exist in any previous versions of OpenSSL. Therefore versions of OpenSSL shipped with Red Hat Enterprise Linux 5, 6, and 7, and JBoss EAP and JBoss Web Server are not vulnerable to this security flaw. Versions of OpenSSL shipped in Red Hat Enterprise Linux do not enable the SSL_OP_SINGLE_DH_USE option. However, most applications do not use SSL_CTX_set_tmp_dh()/SSL_set_tmp_dh(). Most of them use SSL_CTX_set_tmp_dh_callback()/SSL_set_tmp_dh_callback() without setting the key. This has the same effect as setting SSL_OP_SINGLE_DH_USE.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
AV:N/AC:H/Au:N/C:P/I:N/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (55 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 83.64% (0.83645) | 99.68th | v5 (v2026.06.15) |
| Sep 22, 2026 | 83.64% (0.83645) | 99.67th | v5 (v2026.06.15) |
| Sep 21, 2026 | 77.27% (0.77270) | 99.55th | v5 (v2026.06.15) |
| Sep 6, 2026 | 83.64% (0.83645) | 99.67th | v5 (v2026.06.15) |
| Sep 5, 2026 | 77.27% (0.77270) | 99.53th | v5 (v2026.06.15) |
| Aug 30, 2026 | 83.64% (0.83645) | 99.67th | v5 (v2026.06.15) |
| Aug 28, 2026 | 77.27% (0.77270) | 99.53th | v5 (v2026.06.15) |
| Aug 24, 2026 | 83.64% (0.83645) | 99.66th | v5 (v2026.06.15) |
| Aug 23, 2026 | 77.27% (0.77270) | 99.53th | v5 (v2026.06.15) |
| Jun 15, 2026 | 83.64% (0.83645) | 99.65th | v5 (v2026.06.15) |
| Apr 9, 2026 | 27.48% (0.27483) | 96.41th | v4 (v2025.03.14) |
| Mar 22, 2026 | 39.52% (0.39515) | 97.26th | v4 (v2025.03.14) |
| Mar 4, 2026 | 27.48% (0.27483) | 96.32th | v4 (v2025.03.14) |
| Mar 1, 2026 | 14.08% (0.14077) | 94.24th | v4 (v2025.03.14) |
| Feb 19, 2026 | 27.48% (0.27483) | 96.31th | v4 (v2025.03.14) |
| Feb 4, 2026 | 24.99% (0.24988) | 96.02th | v4 (v2025.03.14) |
| Feb 1, 2026 | 16.12% (0.16119) | 94.64th | v4 (v2025.03.14) |
| Jan 4, 2026 | 24.99% (0.24988) | 95.97th | v4 (v2025.03.14) |
| Jan 1, 2026 | 12.53% (0.12535) | 93.75th | v4 (v2025.03.14) |
| Dec 28, 2025 | 24.99% (0.24988) | 95.98th | v4 (v2025.03.14) |
| Dec 27, 2025 | 23.87% (0.23867) | 95.85th | v4 (v2025.03.14) |
| Dec 4, 2025 | 24.99% (0.24988) | 95.95th | v4 (v2025.03.14) |
| Dec 2, 2025 | 12.53% (0.12535) | 93.71th | v4 (v2025.03.14) |
| Dec 1, 2025 | 16.48% (0.16477) | 94.68th | v4 (v2025.03.14) |
| Nov 4, 2025 | 24.99% (0.24988) | 95.92th | v4 (v2025.03.14) |
| Nov 1, 2025 | 16.12% (0.16119) | 94.55th | v4 (v2025.03.14) |
| Oct 28, 2025 | 24.99% (0.24988) | 95.91th | v4 (v2025.03.14) |
| Oct 27, 2025 | 23.87% (0.23867) | 95.78th | v4 (v2025.03.14) |
| Oct 4, 2025 | 24.99% (0.24988) | 95.96th | v4 (v2025.03.14) |
| Oct 1, 2025 | 12.53% (0.12535) | 93.72th | v4 (v2025.03.14) |
| Sep 6, 2025 | 23.87% (0.23867) | 95.81th | v4 (v2025.03.14) |
| Sep 1, 2025 | 12.45% (0.12449) | 93.70th | v4 (v2025.03.14) |
| Aug 4, 2025 | 23.87% (0.23867) | 95.79th | v4 (v2025.03.14) |
| Aug 1, 2025 | 12.45% (0.12449) | 93.67th | v4 (v2025.03.14) |
| Jul 30, 2025 | 23.87% (0.23867) | 95.78th | v4 (v2025.03.14) |
| Jul 4, 2025 | 24.99% (0.24988) | 95.90th | v4 (v2025.03.14) |
| Jul 1, 2025 | 16.12% (0.16119) | 94.53th | v4 (v2025.03.14) |
| Jun 4, 2025 | 24.99% (0.24988) | 95.86th | v4 (v2025.03.14) |
| Jun 1, 2025 | 16.12% (0.16119) | 94.48th | v4 (v2025.03.14) |
| May 4, 2025 | 24.99% (0.24988) | 95.83th | v4 (v2025.03.14) |
| May 1, 2025 | 16.12% (0.16119) | 94.44th | v4 (v2025.03.14) |
| Apr 23, 2025 | 24.99% (0.24988) | 95.80th | v4 (v2025.03.14) |
| Apr 1, 2025 | 30.64% (0.30640) | 96.33th | v4 (v2025.03.14) |
| Mar 30, 2025 | 36.82% (0.36818) | 96.82th | v4 (v2025.03.14) |
| Mar 29, 2025 | 49.00% (0.49005) | 96.75th | v4 (v2025.03.14) |
| Mar 28, 2025 | 36.82% (0.36818) | 96.82th | v4 (v2025.03.14) |
| Mar 20, 2025 | 49.00% (0.49005) | 97.56th | v4 (v2025.03.14) |
| Mar 19, 2025 | 54.16% (0.54156) | 97.72th | v4 (v2025.03.14) |
| Mar 17, 2025 | 49.00% (0.49005) | 97.49th | v4 (v2025.03.14) |
| Dec 12, 2024 | 8.76% (0.08757) | 94.80th | v3 (v2023.03.01) |
| Dec 5, 2024 | 8.76% (0.08757) | 94.78th | v3 (v2023.03.01) |
| Mar 7, 2023 | 11.88% (0.11884) | 94.39th | v3 (v2023.03.01) |
| Mar 6, 2023 | 7.56% (0.07559) | 92.87th | v2 (v2022.01.01) |
| Apr 1, 2022 | 7.56% (0.07559) | 92.17th | v2 (v2022.01.01) |
| Feb 4, 2022 | 7.56% (0.07559) | 81.11th | v2 (v2022.01.01) |
References (29)
- http://intothesymmetry.blogspot.com/2016/01/openssl-key-recovery-attack-on-dh-small.html
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10759
- http://lists.fedoraproject.org/pipermail/package-announce/2016-January/176373.html vendor-advisory
- http://lists.opensuse.org/opensuse-security-announce/2016-03/msg00009.html vendor-advisory
- http://www.openssl.org/news/secadv/20160128.txt Vendor Advisory
- http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- http://www.securityfocus.com/bid/82233 vdb-entry
- http://www.securityfocus.com/bid/91787 vdb-entry
- http://www.securitytracker.com/id/1034849 vdb-entry
- http://www.ubuntu.com/usn/USN-2883-1 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2016-0701 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1301845 Issue Tracking
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://git.openssl.org/?p=openssl.git%3Ba=commit%3Bh=878e2c5b13010329c203f309ed0c8f2113f85648
- https://git.openssl.org/?p=openssl.git%3Ba=commit%3Bh=c5b831f21d0d29d1e517d139d9d101763f60c9a2
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03724en_us
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05164821
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05390893
- https://nvd.nist.gov/vuln/detail/CVE-2016-0701
- https://security.gentoo.org/glsa/201601-05 vendor-advisory
- https://www.cve.org/CVERecord?id=CVE-2016-0701
- https://www.kb.cert.org/vuls/id/257823 third-party-advisory
- https://www.openssl.org/news/secadv/20160128.txt
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujan2020.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html
Change history (0)
No recorded changes yet.