Ubuntu 16.04 LTS / 16.10 : python-cryptography vulnerability (USN-3138-1)

Medium Nessus Plugin ID 95385


The remote Ubuntu host is missing one or more security-related patches.


Markus Doring discovered that python-cryptography incorrectly handled certain HKDF lengths. This could result in python-cryptography returning an empty string instead of the expected derived key.

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.


Update the affected python-cryptography and / or python3-cryptography packages.

Plugin Details

Severity: Medium

ID: 95385

File Name: ubuntu_USN-3138-1.nasl

Version: $Revision: 3.5 $

Type: local

Agent: unix

Published: 2016/11/29

Modified: 2018/01/30

Dependencies: 12634

Risk Information

Risk Factor: Medium


Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

Temporal Vector: CVSS2#E:POC/RL:OF/RC:ND


Base Score: 7.5

Temporal Score: 6.7

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

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:X

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:python-cryptography, p-cpe:/a:canonical:ubuntu_linux:python3-cryptography, cpe:/o:canonical:ubuntu_linux:16.04, cpe:/o:canonical:ubuntu_linux:16.10

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2016/11/28

Reference Information

CVE: CVE-2016-9243

OSVDB: 147018

USN: 3138-1