Debian LTS DLA-3555-1 Critical: PHP 7.3 RCE And DoS Vulnerabilities

CVE-2023-3823

Various XML functions rely on libxml global state to track
configuration variables, like whether external entities are loaded.
This state is assumed to be unchanged unless the user explicitly
changes it by calling appropriate function. Joas Schilling and
Baptista Katapi discovered that, since the state is process-global,
other modules — such as ImageMagick — may also use this library
within the same process and change that global state for their
internal purposes, and leave it in a state where external entities
loading is enabled. This can lead to the situation where external
XML is parsed with external entities loaded, which can lead to
disclosure of any local files accessible to PHP. This vulnerable
state may persist in the same process across many requests, until
the process is shut down.

CVE-2023-3824

Niels Dossche discovered that when loading a Phar file, while