Client DoS due to large DH parameter
Priority HIGH 69CWE-320Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 15 fixed, 7 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack. Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h). Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o).
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.4701 98th percentileScored 2026-11-07
Fix Partial Red Hat: 6 advisoriesRed Hat: 15 fixed, 7 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| OpenSSL | OpenSSL | Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h); Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o) | — | No fix listed | CNA |
- OpenSSL VendorOpenSSL Affected Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h); Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o) Fixed in — No fix listed CNA
CPE configurations NVD · 12
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* | 1.0.2 – 1.0.2o; 1.1.0 – 1.1.0h | Vulnerable | OpenSSL |
| cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:esm:*:*:* | 12.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* | 14.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* | 16.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:* | 17.10 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* | 18.04 | Vulnerable | Canonical |
| cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Debian |
| cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:* | 6.0.0 to before 6.8.1 | Vulnerable | NodeJS |
| cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:* | 6.9.0 to before 6.14.4 | Vulnerable | NodeJS |
| cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:* | 8.0.0 to before 8.8.1 | Vulnerable | NodeJS |
- cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* Versions 1.0.2 – 1.0.2o; 1.1.0 – 1.1.0h Vulnerable ·OpenSSL
- cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:esm:*:*:* Versions 12.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* Versions 14.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* Versions 16.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:* Versions 17.10 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
- cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Debian
- cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:* Versions 6.0.0 to before 6.8.1 Vulnerable ·NodeJS
- cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:* Versions 6.9.0 to before 6.14.4 Vulnerable ·NodeJS
- cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:* Versions 8.0.0 to before 8.8.1 Vulnerable ·NodeJS
Remediation
Red Hat 6 advisories
- RHSA-2019:1543 Released 2019-06-18 · Red Hat rating ImportantRed Hat JBoss Core Services Apache HTTP Server 2.4.29 SP2 security update
- JBoss Core Services Apache HTTP Server 2.4.29 SP2
- RHSA-2019:1297 Released 2019-05-30 · Red Hat rating ImportantRed Hat JBoss Core Services Apache HTTP Server 2.4.29 SP2 security update
- Red Hat JBoss Core Services on RHEL 6 Server jbcs-httpd24-httpd-2.4.29-40.jbcs.el6, jbcs-httpd24-httpd-devel-2.4.29-40.jbcs.el6, jbcs-httpd24-httpd-manual-2.4.29-40.jbcs.el6 +11
- Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-httpd-2.4.29-40.jbcs.el7, jbcs-httpd24-httpd-devel-2.4.29-40.jbcs.el7, jbcs-httpd24-httpd-manual-2.4.29-40.jbcs.el7 +11
- RHSA-2019:1296 Released 2019-05-30 · Red Hat rating ImportantRed Hat JBoss Core Services Apache HTTP Server 2.4.29 SP2 security update
- JBoss Core Services Apache HTTP Server 2.4.29 SP2
Show 3 more Red Hat advisories
- RHSA-2018:3221 Released 2018-10-30 · Red Hat rating Moderateopenssl security, bug fix, and enhancement update
- Red Hat Enterprise Linux Client (v. 7) openssl-1:1.0.2k-16.el7, openssl-libs-1:1.0.2k-16.el7
- Red Hat Enterprise Linux Client Optional (v. 7) openssl-devel-1:1.0.2k-16.el7, openssl-perl-1:1.0.2k-16.el7, openssl-static-1:1.0.2k-16.el7
- Red Hat Enterprise Linux ComputeNode (v. 7) openssl-1:1.0.2k-16.el7, openssl-libs-1:1.0.2k-16.el7
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) openssl-devel-1:1.0.2k-16.el7, openssl-perl-1:1.0.2k-16.el7, openssl-static-1:1.0.2k-16.el7
- Red Hat Enterprise Linux Server (v. 7) openssl-1:1.0.2k-16.el7, openssl-devel-1:1.0.2k-16.el7, openssl-devel-1:1.0.2k-16.el7.ppc +2
- Red Hat Enterprise Linux Server Optional (v. 7) openssl-perl-1:1.0.2k-16.el7, openssl-static-1:1.0.2k-16.el7, openssl-static-1:1.0.2k-16.el7.ppc
- Red Hat Enterprise Linux Workstation (v. 7) openssl-1:1.0.2k-16.el7, openssl-devel-1:1.0.2k-16.el7, openssl-libs-1:1.0.2k-16.el7
- Red Hat Enterprise Linux Workstation Optional (v. 7) openssl-perl-1:1.0.2k-16.el7, openssl-static-1:1.0.2k-16.el7
- Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) openssl-1:1.0.2k-16.el7, openssl-devel-1:1.0.2k-16.el7, openssl-libs-1:1.0.2k-16.el7
- Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) openssl-perl-1:1.0.2k-16.el7, openssl-static-1:1.0.2k-16.el7
- RHSA-2018:2553 Released 2018-08-22 · Red Hat rating ModerateRed Hat OpenShift Application Runtimes Node.js 10.9.0 security update
- Red Hat OpenShift Application Runtimes Node.js 10 npm-1:6.2.0-1.10.9.0.1.el7, rhoar-nodejs-1:10.9.0-1.el7, rhoar-nodejs-docs-1:10.9.0-1.el7
- RHSA-2018:2552 Released 2018-08-22 · Red Hat rating ModerateRed Hat OpenShift Application Runtimes Node.js 8.11.4 security update
- Red Hat OpenShift Application Runtimes Node.js 8 npm-1:5.6.0-1.8.11.4.2.el7, rhoar-nodejs-1:8.11.4-2.el7, rhoar-nodejs-docs-1:8.11.4-2.el7
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Will not fix |
| Red Hat JBoss Enterprise Application Platform 5 | Affected | No fix planned: Out of support scope |
| Red Hat JBoss Enterprise Application Platform 6 | Affected | No fix planned: Will not fix |
| Red Hat JBoss Enterprise Web Server 2 | Affected | No fix planned: Will not fix |
| Red Hat JBoss Web Server 3 | Affected | No fix yet |
| JBoss Core Services Apache HTTP Server 2.4.29 SP2 | Fixed | RHSA-2019:1543 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux ComputeNode (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux ComputeNode Optional (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) | Fixed | RHSA-2018:3221 |
| Red Hat JBoss Core Services on RHEL 6 Server | Fixed | RHSA-2019:1297 |
| Red Hat JBoss Core Services on RHEL 7 Server | Fixed | RHSA-2019:1297 |
| Red Hat OpenShift Application Runtimes Node.js 10 | Fixed | RHSA-2018:2553 |
| Red Hat OpenShift Application Runtimes Node.js 8 | Fixed | RHSA-2018:2552 |
Not affected: 1 product
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2018-0732
- 2026-10-03 Alias added: GHSA-497c-86pp-222m
- 2026-10-08 CISA SSVC decision points changed
- 2026-10-09 Priority changed: MEDIUM → HIGH
References
Patch 5
- http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
- https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.html
- https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
- https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
Advisory 28
- [debian-lts-announce] 20180728 [SECURITY] [DLA 1449-1] openssl security update
- DSA-4355
- RHSA-2018:2552
- GLSA-201811-03
- USN-3692-2
- RHSA-2018:2553
- RHSA-2018:3505
- USN-3692-1
- RHSA-2018:3221
- DSA-4348
- RHSA-2019:1297
- RHSA-2019:1296
- RHSA-2019:1543
- FEDORA-2019-db06efdea1
- FEDORA-2019-00c25b9379
- FEDORA-2019-9a0a7c0986
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.tenable.com/security/tns-2018-14
- https://securityadvisories.paloaltonetworks.com/Home/Detail/133
- https://www.tenable.com/security/tns-2018-13
- https://www.tenable.com/security/tns-2018-17
- https://www.tenable.com/security/tns-2018-12
- https://security.netapp.com/advisory/ntap-20181105-0001/
- https://nodejs.org/en/blog/vulnerability/august-2018-security-releases/
- https://www.openssl.org/news/secadv/20180612.txt
- https://security.netapp.com/advisory/ntap-20190118-0002/
- https://cert-portal.siemens.com/productcert/pdf/ssa-419820.pdf
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Sources
- CVE-2018-0732 · CVE Program
- CVE-2018-0732 · NVD
- FIRST EPSS
- GHSA-497c-86pp-222m · GitHub Advisory Database · CC BY 4.0
- CVE-2018-0732 · Red Hat security data · CC BY 4.0
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