==========================================================================
Ubuntu Security Notice USN-4267-1
February 05, 2020

mbedtls vulnerabilities
==========================================================================

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

- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in mbedtls.

Software Description:
- mbedtls: lightweight crypto and SSL/TLS library - crypto library

Details:

It was discovered that mbedtls has a bounds-check bypass through an integer
overflow that can be used by an attacked to execute arbitrary code or cause a
denial of service.
(CVE-2017-18187)

It was discovered that mbedtls has a vulnerability where an attacker could
execute arbitrary code or cause a denial of service (buffer overflow)
via a crafted certificate chain that is mishandled during RSASSA-PSS
signature verification within a TLS or DTLS session.
(CVE-2018-0487)

It was discovered that mbedtls has a vulnerability where an attacker could
execute arbitrary code or cause a denial of service (heap corruption) via a
crafted application packet within a TLS or DTLS session.
(CVE-2018-0488)

It was discovered that mbedtls has a vulnerability that allows remote
attackers to achieve partial plaintext recovery (for a CBC based ciphersuite)
via a timing-based side-channel attack.
(CVE-2018-0497)

It was discovered that mbedtls has a vulnerability that allows local users to
achieve partial plaintext recovery (for a CBC based ciphersuite) via a
cache-based side-channel attack.
(CVE-2018-0498)

Update instructions:

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

Ubuntu 16.04 LTS:
  libmbedcrypto0                  2.2.1-2ubuntu0.3
  libmbedtls10                    2.2.1-2ubuntu0.3
  libmbedx509-0                   2.2.1-2ubuntu0.3

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

References:
  https://usn.ubuntu.com/4267-1
  CVE-2017-18187, CVE-2018-0487, CVE-2018-0488, CVE-2018-0497,
  CVE-2018-0498

Package Information:
  https://launchpad.net/ubuntu/+source/mbedtls/2.2.1-2ubuntu0.3