CVE-2016-0739

Publication date 23 February 2016

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

libssh before 0.7.3 improperly truncates ephemeral secrets generated for the (1) diffie-hellman-group1 and (2) diffie-hellman-group14 key exchange methods to 128 bits, which makes it easier for man-in-the-middle attackers to decrypt or intercept SSH sessions via unspecified vectors, aka a "bits/bytes confusion bug."

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libssh	16.10 yakkety	Fixed 0.6.3-4.2ubuntu1
	16.04 LTS xenial	Fixed 0.6.3-4.2ubuntu1
	15.10 wily	Fixed 0.6.3-3ubuntu3.2
	14.04 LTS trusty	Fixed 0.6.1-0ubuntu3.3
	12.04 LTS precise	Fixed 0.5.2-1ubuntu0.12.04.6

Notes

tyhicks

affects "all versions of libssh 0.1 and later"

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:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-2912-1
libssh vulnerabilities
23 February 2016