--- title: "CVE-2018-0734\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2018-0734?format=md keywords: index, follow --- # CVE-2018-0734 Publication date 30 October 2018 Last updated 25 August 2025 --- Ubuntu priority **Low** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **5.9 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2018-0734?format=md#impact-score) Toggle side navigation ## Description The OpenSSL DSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key. Fixed in OpenSSL 1.1.1a (Affected 1.1.1). Fixed in OpenSSL 1.1.0j (Affected 1.1.0-1.1.0i). Fixed in OpenSSL 1.0.2q (Affected 1.0.2-1.0.2p). [Read the notes from the security team](https://ubuntu.com/security/CVE-2018-0734?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | openssl | 21.04 hirsute | Fixed 1.1.1a-1ubuntu2 | | 20.10 groovy | Fixed 1.1.1a-1ubuntu2 | | 20.04 LTS focal | Fixed 1.1.1a-1ubuntu2 | | 19.10 eoan | Fixed 1.1.1a-1ubuntu2 | | 19.04 disco | Fixed 1.1.1a-1ubuntu2 | | 18.10 cosmic | Fixed 1.1.1-1ubuntu2.1 | | 18.04 LTS bionic | Fixed 1.1.0g-2ubuntu4.3 | | 16.04 LTS xenial | Fixed 1.0.2g-1ubuntu4.14 | | 14.04 LTS trusty | Fixed 1.0.1f-1ubuntu2.27 | | openssl098 | 21.04 hirsute | Not in release | | 20.10 groovy | Not in release | | 20.04 LTS focal | Not in release | | 19.10 eoan | Not in release | | 19.04 disco | Not in release | | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | openssl1.0 | 21.04 hirsute | Not in release | | 20.10 groovy | Not in release | | 20.04 LTS focal | Not in release | | 19.10 eoan | Not in release | | 19.04 disco | Not in release | | 18.10 cosmic | Fixed 1.0.2n-1ubuntu6.1 | | 18.04 LTS bionic | Fixed 1.0.2n-1ubuntu5.2 | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) * [Patch details](https://ubuntu.com/security/CVE-2018-0734?format=md#patch-details) ## Notes --- ### [mdeslaur](https://launchpad.net/~mdeslaur) there are other similar commits in crypto/dsa/dsa\_ossl.c that likely need backporting also. upstream advisory was ammended with more commits ### Patch details For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) | Package | Patch details | | --- | --- | | openssl | * Upstream: * Upstream: * Upstream: * Upstream: * Upstream: * Upstream: * Upstream: * Upstream: * Upstream: | ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 5.9 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Network | | Attack complexity | High | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | High | | Integrity impact | None | | Availability impact | None | * Scores | Parameter | Value | | --- | --- | | Base score | 5.9 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-0734) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-0734) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-0734) * [Debian](https://security-tracker.debian.org/tracker/CVE-2018-0734) ### Related Ubuntu Security Notices (USN) + [USN-3840-1](https://usn.ubuntu.com/USN-3840-1) + OpenSSL vulnerabilities + 6 December 2018 ### Other references * *