Several security issues were fixed in Perl.
It was discovered that Perl incorrectly handled certain regular expressions. An attacker could possibly use this issue to cause Perl to hang, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2015-8853)
16 April 2018
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in Perl.
It was discovered that Perl incorrectly handled certain regular expressions. An attacker could possibly use this issue to cause Perl to hang, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2015-8853)
It was discovered that Perl incorrectly loaded libraries from the current working directory. A local attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-6185)
It was discovered that Perl incorrectly handled the rmtree and remove_tree functions. A local attacker could possibly use this issue to set the mode on arbitrary files. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2017-6512)
Brian Carpenter discovered that Perl incorrectly handled certain regular expressions. An attacker could use this issue to cause Perl to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue has only been addressed in Ubuntu 16.04 LTS and Ubuntu 17.10. (CVE-2018-6797)
Nguyen Duc Manh discovered that Perl incorrectly handled certain regular expressions. An attacker could use this issue to cause Perl to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS and Ubuntu 17.10. (CVE-2018-6798)
GwanYeong Kim discovered that Perl incorrectly handled certain data when using the pack function. An attacker could use this issue to cause Perl to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2018-6913)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.