==========================================================================
Ubuntu Security Notice USN-4127-1
September 09, 2019

python2.7, python3.5, python3.6, python3.7 vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in Python.

Software Description:
- python2.7: An interactive high-level object-oriented language
- python3.7: An interactive high-level object-oriented language
- python3.6: An interactive high-level object-oriented language
- python3.5: An interactive high-level object-oriented language

Details:

It was discovered that Python incorrectly handled certain pickle files. An
attacker could possibly use this issue to consume memory, leading to a
denial of service. This issue only affected Ubuntu 16.04 LTS and Ubuntu
18.04 LTS. (CVE-2018-20406)

It was discovered that Python incorrectly validated the domain when
handling cookies. An attacker could possibly trick Python into sending
cookies to the wrong domain. (CVE-2018-20852)

Jonathan Birch and Panayiotis Panayiotou discovered that Python incorrectly
handled Unicode encoding during NFKC normalization. An attacker could
possibly use this issue to obtain sensitive information. (CVE-2019-9636,
CVE-2019-10160)

Colin Read and Nicolas Edet discovered that Python incorrectly handled
parsing certain X509 certificates. An attacker could possibly use this
issue to cause Python to crash, resulting in a denial of service. This
issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2019-5010)

It was discovered that Python incorrectly handled certain urls. A remote
attacker could possibly use this issue to perform CRLF injection attacks.
(CVE-2019-9740, CVE-2019-9947)

Sihoon Lee discovered that Python incorrectly handled the local_file:
scheme. A remote attacker could possibly use this issue to bypass blacklist
meschanisms. (CVE-2019-9948)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 19.04:
  python2.7                       2.7.16-2ubuntu0.1
  python2.7-minimal               2.7.16-2ubuntu0.1
  python3.7                       3.7.3-2ubuntu0.1
  python3.7-minimal               3.7.3-2ubuntu0.1

Ubuntu 18.04 LTS:
  python2.7                       2.7.15-4ubuntu4~18.04.1
  python2.7-minimal               2.7.15-4ubuntu4~18.04.1
  python3.6                       3.6.8-1~18.04.2
  python3.6-minimal               3.6.8-1~18.04.2

Ubuntu 16.04 LTS:
  python2.7                       2.7.12-1ubuntu0~16.04.8
  python2.7-minimal               2.7.12-1ubuntu0~16.04.8
  python3.5                       3.5.2-2ubuntu0~16.04.8
  python3.5-minimal               3.5.2-2ubuntu0~16.04.8

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4127-1
  CVE-2018-20406, CVE-2018-20852, CVE-2019-10160, CVE-2019-5010,
  CVE-2019-9636, CVE-2019-9740, CVE-2019-9947, CVE-2019-9948

Package Information:
  https://launchpad.net/ubuntu/+source/python2.7/2.7.16-2ubuntu0.1
  https://launchpad.net/ubuntu/+source/python3.7/3.7.3-2ubuntu0.1
  https://launchpad.net/ubuntu/+source/python2.7/2.7.15-4ubuntu4~18.04.1
  https://launchpad.net/ubuntu/+source/python3.6/3.6.8-1~18.04.2
  https://launchpad.net/ubuntu/+source/python2.7/2.7.12-1ubuntu0~16.04.8
  https://launchpad.net/ubuntu/+source/python3.5/3.5.2-2ubuntu0~16.04.8