# CVE-2018-0732: Client DoS due to large DH parameter

CVE-2018-0732 is fixed in 5 products on 2 platforms, first by libssl1.0.0 1.0.2n-1ubuntu5.1, released June 12, 2018. 1 other affected product has no fix yet. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2018-0732
- Priority: High
- CVSS: 7.5 (Low)
- EPSS: 0.4701
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 11, 2018
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2018-0732

## 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).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Node.js 6 | 6.17.0 | [Node.js 6 6.17.0](https://patchblox.com/security/data/fix/windows-app/openjs.nodejs.6-6.17.0.md) | Feb 28, 2019 |
| Linux | libssl1.0.0 Ubuntu 18.04.6 LTS (bionic) | 1.0.2n-1ubuntu5.1 | [libssl1.0.0 1.0.2n-1ubuntu5.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libssl1.0.0-1.0.2n-1ubuntu5.1.md) | Jun 12, 2018 |
| Linux | libssl1.1 Ubuntu 18.04.6 LTS (bionic) | 1.1.0g-2ubuntu4.1 | [libssl1.1 1.1.0g-2ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libssl1.1-1.1.0g-2ubuntu4.1.md) | Jun 12, 2018 |
| Linux | openssl Ubuntu 18.04.6 LTS (bionic) | 1.1.0g-2ubuntu4.1 | [openssl 1.1.0g-2ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-openssl-1.1.0g-2ubuntu4.1.md) | Jun 12, 2018 |
| Linux | openssl1.0 Ubuntu 18.04.6 LTS (bionic) | 1.0.2n-1ubuntu5.1 | [openssl1.0 1.0.2n-1ubuntu5.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-openssl1.0-1.0.2n-1ubuntu5.1.md) | Jun 12, 2018 |

## No fix yet

| Platform | Product | Status |
|---|---|---|
| Windows apps | Node.js 8 | no-fix |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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