Steps to reproduce the issue

Go to:

• Content
• Articles
• New
• Populate Title field
• In Article Test field add the following text:
  ..\..\..\..
• Save

Expected result

Redirect back to "Article Saved." prompt

Actual result

From Vivaldi Web Browser:
"This page isn’t working
ERR_EMPTY_RESPONSE"
(Article doesn't save)

Firefox (Internet Security software):
"This page was blocked for your protection"
(Article saves)

System information (as much as possible)

Vanilla Joomla 5.2.0 instance
Tried on the following hosts:

• IONOS
• Basic Ubuntu Virtual Machine LAMP (Linux, Apache, MySQL, PHP) setup

Additional comments

On the Ubuntu Lamp instance it wouldn't save, but it does in IONOS but not before the internet security software blocks access right after.