Firefox browser will soon prevent the injection of DLL files from anti-virus and other third-party applications.
Windows antivirus and other third-party applications, such as PDF tools, etc., tend to add DLLs to the browser. This behavior is known to cause stability problems for browser users.
Mozilla seems to be following in the footsteps of Google, which began blocking third-party code injection into Google Chrome in 2018. Google found that Chrome-based third-party DLL installations had 15% more problems than Chrome installations which did not contain third party DLLs.
According to gHacks The Mozilla Foundation began investigating third-party DLL disabling in Firefox in the fourth quarter of 2016, but apparently decisions have already been made.
Firefox Nightly is already blocking the addition of third-party DLLs. The feature will be later integrated into the Beta and stable versions of Firefox browser, from version 66.
Firefox Beta will reach version 66 on January 29, 2019 and Firefox Stable will release version 66 on March 19, 2019.
How do you know if the security feature is already enabled? It's simple: Open the about: support internal address and check the process entry at the top.
If enabled and you want to disable the new feature (available only in Firefox Nightly) open the following internal address:
about: config? filter = browser.launcherProcess.enabled
Enabling the feature can cause problems in third-party applications, which will need to update their applications by Firefox version 66 to remove any DLLs they add to the browser.