smarty3 vulnerabilities

USN-5348-1 fixed several vulnerabilities in Smarty. This update provides
the fixes for CVE-2021-21408, CVE-2021-26119, CVE-2021-26120 and
CVE-2021-29454 for Ubuntu 20.04 ESM.

Original advisory details:

David Gnedt and Thomas Konrad discovered that Smarty was incorrectly
sanitizing the paths present in the templates. An attacker could possibly
use this use to read arbitrary files when controlling the executed
template. (CVE-2018-13982)

It was discovered that Smarty was incorrectly sanitizing the paths
present in the templates. An attacker could possibly use this use to read
arbitrary files when controlling the executed template. (CVE-2018-16831)

It was discovered that Smarty was incorrectly validating security policy
data, allowing the execution of static classes even when not permitted by
the security settings. An attacker could possibly use this issue to
execute arbitrary code. (CVE-2021-21408)

It was discovered that Smarty was incorrectly managing access control to
template objects, which allowed users to perform a sandbox escape. An
attacker could possibly use this issue to send specially crafted input to
applications that use Smarty and execute arbitrary code. (CVE-2021-26119)

It was discovered that Smarty was not checking for special characters
when setting function names during plugin compile operations. An attacker
could possibly use this issue to send specially crafted input to
applications that use Smarty and execute arbitrary code. (CVE-2021-26120)

It was discovered that Smarty was incorrectly sanitizing characters in
math strings processed by the math function. An attacker could possibly
use this issue to send specially crafted input to applications that use
Smarty and execute arbitrary code. (CVE-2021-29454)