# CVE-2018-0732: Client DoS due to large DH parameter > A malicious server can cause a client hang and denial of service by sending a large DH parameter during TLS handshake. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 12 Jun 2018 - **Updated:** 8 Oct 2026 - **Also known as:** ALPINE-CVE-2018-0732, DEBIAN-CVE-2018-0732, GHSA-497c-86pp-222m, SUSE-SU-2018:1887-1, SUSE-SU-2018:1887-2, SUSE-SU-2018:1968-1, SUSE-SU-2018:2036-1, SUSE-SU-2018:2041-1, SUSE-SU-2018:2207-1, SUSE-SU-2018:2956-1, UBUNTU-CVE-2018-0732 ## What is CVE-2018-0732? CVE-2018-0732 is a high-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 12 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description 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). Weakness: CWE-320 ## Which versions are affected by CVE-2018-0732? It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `openssl` | SUSE:Enterprise Storage 4 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Desktop 12 SP3 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 1.1.0i-3.3.1 | | `openssl-1_1` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 1.1.0h-4.3.1 | | `openssl-1_1` | SUSE:Linux Enterprise Module for Basesystem 15 | All versions | 1.1.0i-4.9.2 | | `openssl-1_0_0` | SUSE:Linux Enterprise Module for Legacy 15 | All versions | 1.0.2n-3.3.1 | | `openssl` | SUSE:Linux Enterprise Point of Sale 11 SP3 | All versions | 0.9.8j-0.106.12.1 | | `openssl` | SUSE:Linux Enterprise Server 11 SP3-LTSS | All versions | 0.9.8j-0.106.12.1 | | `openssl` | SUSE:Linux Enterprise Server 11 SP3-TERADATA | All versions | 0.9.8j-0.106.12.1 | | `openssl` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 0.9.8j-0.106.12.1 | | `openssl` | SUSE:Linux Enterprise Server 12 SP1-LTSS | All versions | 1.0.1i-54.14.1 | | `openssl` | SUSE:Linux Enterprise Server 12 SP2-BCL | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Server 12 SP2-LTSS | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Server 12 SP3 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 0.9.8j-0.106.12.1 | | `openssl` | SUSE:Linux Enterprise Server for SAP Applications 12 SP1 | All versions | 1.0.1i-54.14.1 | | `openssl` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Linux Enterprise Software Development Kit 11 SP4 | All versions | 0.9.8j-0.106.12.1 | | `openssl` | SUSE:Linux Enterprise Software Development Kit 12 SP3 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:OpenStack Cloud 7 | All versions | 1.0.2j-60.30.1 | | `openssl` | SUSE:Studio Onsite 1.3 | All versions | 0.9.8j-0.106.12.1 | Products: Canonical Ubuntu Linux, Debian Debian Linux, Nodejs Node.js, Openssl Openssl. ## How do I fix CVE-2018-0732? Upgrade to a fixed version. ## Is CVE-2018-0732 being exploited? There is no known exploitation of CVE-2018-0732 in the wild and no public exploit code. ## Other vulnerabilities in Canonical Ubuntu Linux - [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild) - [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2018-0732 and fix it if it is affected. What it is: CVE-2018-0732 is a high-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 12 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2018-0732 in the wild and no public exploit code. Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2018-0732/ (Markdown: https://insights.sbomify.com/CVE-2018-0732/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0732 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0732 - OSV: https://osv.dev/vulnerability/CVE-2018-0732 --- From sbomify Insights: https://insights.sbomify.com/CVE-2018-0732/ Summaries are generated and may contain mistakes; the official description above is the record.