---
title: "CVE-2018-0735\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-2018-0735?format=md
keywords: index, follow
---

# CVE-2018-0735

Publication date 29 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-2018-0735?format=md#impact-score)

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## Description

The OpenSSL ECDSA 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 1.1.0j (Affected
1.1.0-1.1.0i). Fixed in OpenSSL 1.1.1a (Affected 1.1.1).

[Read the notes from the security team](https://ubuntu.com/security/CVE-2018-0735?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 | Not affected |
| 14.04 LTS trusty | Not affected |
| 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 | Not affected |
| 18.04 LTS bionic | Not affected |
| 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-2018-0735?format=md#patch-details)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

this may be introduced by the fix for CVE-2018-5407

### 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:   <https://git.openssl.org/?p=openssl.git;a=commit;h=b1d6d55ece1c26fa2829e2b819b038d7b6d692b4> * Upstream:   <https://git.openssl.org/?p=openssl.git;a=commit;h=56fb454d281a023b3f950d969693553d3f3ceea1> * Upstream:   <https://git.openssl.org/?p=openssl.git;a=commit;h=003f1bfd185267cc67ac9dc521a27d7a2af0d0ee> |

## 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-2018-0735)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-0735)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-0735)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-0735)

### Related Ubuntu Security Notices (USN)

+ [USN-3840-1](https://usn.ubuntu.com/USN-3840-1)
+ OpenSSL vulnerabilities
+ 6 December 2018

### Other references

* <https://www.openssl.org/news/secadv/20181029.txt>
* <https://www.cve.org/CVERecord?id=CVE-2018-0735>