CVE-2016-9243 Improper input validation in cryptography

What is CVE-2016-9243?

CVE-2016-9243 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 27 Mar 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.

Which versions are affected by CVE-2016-9243?

3 open source packages ship an affected version, including cryptography. It affects 3 products.

Products include Canonical Ubuntu Linux, Cryptography.io Cryptography, Fedoraproject Fedora.

How do I fix CVE-2016-9243?

Upgrade cryptography to 1.5.3 or later.

Is CVE-2016-9243 being exploited?

There is no known exploitation of CVE-2016-9243 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2016-9243, GHSA-q3cj-2r34-2cwc, MGASA-2016-0377, PYSEC-2017-8, UBUNTU-CVE-2016-9243, USN-3138-1.