Smarty_Security::isTrustedResourceDir() in Smarty before 3.1.33 is prone to a path traversal vulnerability due to insufficient template code sanitization. This allows attackers controlling the executed template code to bypass the trusted directory security restriction and read arbitrary files.
github.com/sbaresearch/advisories/tree/public/2018/SBA-ADV-20180420-01_Smarty_Path_Traversal
github.com/smarty-php/smarty/commit/2e081a51b1effddb23f87952959139ac62654d50
github.com/smarty-php/smarty/commit/8d21f38dc35c4cd6b31c2f23fc9b8e5adbc56dfe
github.com/smarty-php/smarty/commit/bcedfd6b58bed4a7366336979ebaa5a240581531
github.com/smarty-php/smarty/commit/c9dbe1d08c081912d02bd851d1d1b6388f6133d1
github.com/smarty-php/smarty/commit/f9ca3c63d1250bb56b2bda609dcc9dd81f0065f8
lists.debian.org/debian-lts-announce/2021/04/msg00004.html
lists.debian.org/debian-lts-announce/2021/04/msg00014.html
lists.debian.org/debian-lts-announce/2021/10/msg00015.html