CVE-2016-6329

Publication date 31 January 2017

Last updated 25 August 2025

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

5.9 · Medium

Score breakdown

Description

OpenVPN, when using a 64-bit block cipher, makes it easier for remote attackers to obtain cleartext data via a birthday attack against a long-duration encrypted session, as demonstrated by an HTTP-over-OpenVPN session using Blowfish in CBC mode, aka a "Sweet32" attack.

Read the notes from the security team

Status

Package Ubuntu Release Status
openvpn 21.04 hirsute
Not affected
20.10 groovy
Not affected
20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Not affected
18.04 LTS bionic
Not affected
17.10 artful
Not affected
17.04 zesty
Not affected
16.10 yakkety
Fixed 2.3.11-1ubuntu2.1
16.04 LTS xenial
Fixed 2.3.10-1ubuntu2.1
14.04 LTS trusty
Fixed 2.3.2-7ubuntu3.2
12.04 LTS precise Ignored end of life

Notes

mdeslaur

openvpn 2.3 and earlier use BF-CBC by default unless the cipher is specified manually. 2.3.12 was modified to display a warning if a 64-bit cipher is selected. Since this is just a warning, downgrading priority to low

sbeattie

fixed in 2.4.0

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
openvpn

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)

Other references