The smarty_function_math function in libs/plugins/function.math.php in Smarty 2.6.22 allows context-dependent attackers to execute arbitrary commands via shell metacharacters in the equation attribute of the math function. NOTE: some of these details are obtained from third party information.
https://www.redhat.com/archives/fedora-package-announce/2009-May/msg01287.html
https://www.redhat.com/archives/fedora-package-announce/2009-May/msg01283.html
https://www.redhat.com/archives/fedora-package-announce/2009-May/msg01274.html
https://www.exploit-db.com/exploits/8659
https://exchange.xforce.ibmcloud.com/vulnerabilities/50457
http://www.ubuntu.com/usn/usn-791-3
http://secunia.com/advisories/35219