USN-4166-1 fixed a vulnerability in PHP. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM.
Original advisory details:
It was discovered that PHP incorrectly handled certain paths when being used in FastCGI configurations. A remote attacker could possibly use this issue to execute arbitrary code.
{
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libapache2-mod-php5",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "libapache2-mod-php5filter",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "libphp5-embed",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php-pear",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-cgi",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-cli",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-common",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-curl",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-dev",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-enchant",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-fpm",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-gd",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-gmp",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-intl",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-ldap",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-mysql",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-mysqlnd",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-odbc",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-pgsql",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-pspell",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-readline",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-recode",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-snmp",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-sqlite",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-sybase",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-tidy",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-xmlrpc",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        },
        {
            "binary_name": "php5-xsl",
            "binary_version": "5.5.9+dfsg-1ubuntu4.29+esm6"
        }
    ]
}
          {
    "cves": [
        {
            "id": "CVE-2019-11043",
            "severity": [
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        }
    ],
    "ecosystem": "Ubuntu:Pro:14.04:LTS"
}