CVE-2018-0735

Publication date 29 October 2018

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

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

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

Notes

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?

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

Parameter	Value
Base score	5.9 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	None
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-3840-1
OpenSSL vulnerabilities
6 December 2018