Accessibility Services

This article describes a feature that will be available in Firefox version 57 and above.

What are Accessibility Services?

Browser extensibility application programming interfaces (apis) available to applications running on the same device. These apis provide these applications with the ability to inspect, visualize, and change web page content hosted within Firefox.

What are Accessibility Services used for?

  • Accessibility services are primarily consumed by accessibility clients such as screen reading assistive applications designed to help users with vision impairments access the internet.
  • Accessibility services are occasionally consumed by niche software applications that interact with your web browser to accomplish unique tasks or duties. Examples include: automatic web page form filling, time use tracking, corporate sign-on and content monitoring applications, and remote access through remote desktop technologies.
  • Accessibility services can be abused by malware, if present, to monitor user behavior or access user information on the web.

What is the impact of running with Accessibility Services in use?

  • Accessibility services negatively impact Firefox performance.
  • 3rd party applications may be monitoring your web surfing activity.

My Accessibility Services indicator is visible, what does this mean?

Accessibility Services A 3rd party application is accessing your browser through Accessibility Services. Investigate what software is accessing your browser to determine if you feel those services are needed:

  1. Enter about:support in the address bar. The Troubleshooting Information page will open.
  2. Find the "Accessibility" section and look at the value in the "Accessibility Instantiator" entry.
  • blank - No client information was retrieved
  • An application path that points to the program that accessed accessibility services. For example: "C:\Windows\System32\Magnify.exe"
  • An encoded value, for example: '0x800'. Indicates Firefox detected a known accessibility client or screen reader. Listed below are common values and a description of the client detected.
0x1 or 0xNN1, where 'N' can be some other valueNVDA screen reader
0x2 or 0xNN2, where 'N' can be some other valueA compatible version of JAWS screen reader
0x4 or 0xNN4, where 'N' can be some other valueAn incompatible version of JAWS screen reader detected
0x400 or 0x4NN, where 'N' can be some other valueAn unknown out-of-process client was detected.
0x800 or 0x8NN, where 'N' can be some other valueAn UIAutomation client was detected.
  • Both of the above values, separated by a pipe symbol ('|').

Should I disable Accessibility Services?

  • Maybe, are you using any assistive technologies that might rely on accessibility services? If so you should continue to allow accessibility services.
  • View about:support information to try to determine which application is accessing accessibility services. If identified, decide if the application is conducting valid work. If not, consider uninstalling the application or disabling accessibility services within Firefox.
  • Try experimenting: disable accessibility services, restart Firefox and test your browser for a while. If you run into issues with 3rd party programs that interact with Firefox consider enabling accessibility service again.

How do I disable Accessibility Services?

  • If the application responsible can be identified consider uninstalling it. If the application can't be uninstalled consider disabling Accessibility Services (see below).
  • To disable services:
    1. Click the menu button New Fx Menu Fx57Menu and choose Options.Preferences.
    2. Select the Privacy and Security panel.
    3. Go to the "Permissions" section.
    4. Check the Prevent accessibility services from accessing your browser checkbox.
    5. Restart Firefox.

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