Dear Maintainer,
*** Reporter, please consider answering these questions, where appropriate ***
* What led up to the situation?
I have an Debian server with Apache which is serving various PHP applications
* What exactly did you do (or not do) that was effective (or
ineffective)?
I start apt dist-upgrade which updated apache2 to a newer version
* What was the outcome of this action?
During the run of apt dist-upgrade, apache suddenly delivered the .php files uninterpreted in cleartext to the clients, revealing any secrets, database connection strings, passwords, API keys, ... to the user requesting the page.
After apt dist-upgrade was complete, apache correctly interpreted the .php files again
* What outcome did you expect instead?
I would have expected apache2 to not leak the .php sourcecodes, to either correctly interpret .php files during the migration, or to have apache2 stopped during the migration if that is not possible.
I have sent this report to the Debian Security Team first, and they told me to file a public report instead.