This article describes how to troubleshoot problems connecting to websites that start immediately after updating Firefox to a new version. Follow the instructions in this article if you can connect to websites using another browser (such as Internet Explorer Safari Epiphany), but not in Firefox.If no browsers can load websites, see Firefox and other browsers can't load websites.
Mozilla Firefox 72 is a fast, secure and easy to use web browser. As it is powered by a new Quantum engine, Firefox has doubled its speed. And the result of that is the new generation of Web discovery - a more intuitive and useful browser. Firefox 72 is a lean, mean browsing machine. I am using Firefox 78, so my answer is referred to that version, i think in Firefox 72 should be the same. BTW: why Firefox 72? The last version of release channel is 78.0.2, and the last version of esr channel is Firefox 68.10.0. 1.Your MacType profile must contain DirectWrite=1.
At times, Firefox may require significant system resources in order to download, process, and display web content. If you are experiencing periods of sustained high resource usage while using Firefox, this article presents some options for you to review.
- The CPU (Central Processing Unit) is the 'brain' of the computer.
- The RAM (Random Access Memory) or Memory helps your computer perform multiple tasks at the same time.
- When your system resources are being heavily used, the overall performance and stability of the computer can be impacted.
- Depending on your operating system, you can review and monitor resource usage through specific tools. See the Use additional troubleshooting tools section below for more information.
Note: If you send performance data, Mozilla will gather data including memory and CPU usage, which will help make Firefox better for future versions.
Table of Contents
- 12Use additional troubleshooting tools
The latest Firefox version may include performance improvements. Update Firefox to the latest release.
Firefox may use more system resources if it's left open for long periods of time. A workaround for this is to periodically restart Firefox. You can configure Firefox to save your tabs and windows so that when you start it again, you can start where you left off. See Restore previous session - Configure when Firefox shows your most recent tabs and windows for details.
Extensions and themes can cause Firefox to use more system resources than it normally would.
To determine if an extension or theme is causing Firefox to use too many resources, start Firefox in its Safe Mode and observe its memory and CPU usage. In Safe Mode, extensions and themes are disabled, so if you notice a significant improvement, you can try disabling or uninstalling extensions.
- For more information on starting Firefox in Safe Mode and on how to find which extension or theme is causing your problem, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.
Many web pages have content you don't need, but which still use system resources to display its content. Firefox's built-in content blocking can help save resources by preventing third-party tracking content from loading. See the Content blockingEnhanced Tracking Protection article for details.
Some extensions allow you to block unnecessary content; for example:
- Adblock Plus and uBlock Origin allow you to hide ads on websites.
- NoScript allows you to selectively enable and disable scripts running on websites.
If Adobe's Flash Player plugin is installed, rendering Flash content in full screen can be accelerated by hardware. This can ease resource usage in case of a dedicated graphics card.
- Navigate to a page that shows a Flash video.
- Right-clickHold down the Ctrl key while you click on the video player and click Settings… in the context menu. The Adobe Flash Player Settings screen will open.
- Click on the icon at the bottom-left of the Adobe Flash Player Settings window to open the Display panel.
- Check Enable hardware acceleration is selected.
- Click to close the Adobe Flash Player Settings Window.
Each tab requires Firefox to store a web page in memory. If you frequently have more than 100 tabs open, consider using a more lightweight mechanism to keep track of pages to read and things to do, such as:
- Bookmarks. Hint: 'Bookmark All Tabs' will bookmark a set of tabs.
- Save web pages for later with Pocket for Firefox.
- To-do list applications.
Firefox hardware acceleration eases memory and CPU usage in many cases.Check in Firefox's performance settings that hardware acceleration is turned on. Also make sure that your graphics drivers are up-to-date.
With Multiprocess Firefox, also called electrolysis or e10s , Firefox runs web content for all tabs separately from the main Firefox process for increased security and performance. Using multiple content processes can further increase performance and minimize the impact of content process crashes. You can modify Firefox's performance settings to change the content process limit.
You can set between one and eight content processes. The default is eight. Having more content processes can improve performance when using multiple tabs but it will also use more memory. You can reduce the number of content processes if your computer is running out of memory.
Having many applications running simultaneously may cause your computer to run slowly and other applications to do so as well. By closing down some of the unnecessary applications, system usage will be reduced.
Firefox stores your data in various files in your profile folder. The file used for saving individual website settings might be corrupt. If you delete (or rename) that file, your zoom level settings will be reset but it could decrease CPU usage.
- Click the menu button , click Help and select Troubleshooting Information.From the Help menu, select Troubleshooting Information. The Troubleshooting Information tab will open.
- Under the Application Basics section next to Profile FolderDirectory, click . A window will open that contains your profile folder.Your profile folder will open.
Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.- Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit.
- In your profile folder, delete the file content-prefs.sqlite. It will be recreated next time you open Firefox.
The Refresh Firefox feature can fix many issues by restoring your Firefox profile to its default state while saving your essential information.See Refresh Firefox - reset add-ons and settings for details.
There are a variety of troubleshooting tools that can be used both in Firefox and on your operating system to troubleshoot elevated system resource usage.
Firefox tools
- The Firefox Task Manager (not to be confused with Windows Task Manager) is a great tool to see what tabs and extensions are using the most system resources.
- The about:memory page allows you to troubleshoot specific issues relating to memory (for instance, caused by a website, an extension, a theme, etc.) and sometimes its button may help you instantly reduce memory usage. For guidance on use of about:memory visit about:memory.
- Even if you're not a programmer, you can try your hand at some other tools and tips Firefox developers use to debug leaks.
Operating system tools
- View how system resources are being used by checking the Windows Task ManagerPerformance tab (click on 'More details' in the Task Manager to show all tabs). See this Windows blog post at Microsoft's site for more information.
- View how system resources are being used by checking Activity Monitor. See How to use Activity Monitor on your Mac at Apple's site for more information.
- Although it's not included on every distribution of Linux, most versions of Linux have a graphical resource monitor. It's often called System Monitor, but there are other alternatives also available.
- Running the
topcommand in the terminal will display a list of all the running processes and their system resource consumption.
WARNING: There are a variety of third-party programs that promise to increase your computer's performance. You should exercise caution when installing third-party software and only use reputable software provided by an official source.
If you exhausted all tips in the previous sections and your memory usage is still close to the maximum, maybe it's time for you to add more memory to your computer. Adding RAM will provide a huge performance boost.
If you exhausted all tips in the previous sections and you are still experiencing high system resource usage, it may be time to upgrade your computer. As technology progresses, software is becoming more advanced and requires more powerful computers to run effectively.
Security Vulnerabilities fixed in Firefox 72
- Firefox 72
#CVE-2019-17015: Memory corruption in parent process during new content process initialization on Windows
- Reporter
- Thomas Imbert
- Impact
- high
Description
During the initialization of a new content process, a pointer offset can be manipulated leading to memory corruption and a potentially exploitable crash in the parent process.
Note: this issue only occurs on Windows. Other operating systems are unaffected.
References
#CVE-2019-17016: Bypass of @namespace CSS sanitization during pasting
Firefox 72 Issues
- Reporter
- Michał Bentkowski
- Impact
- high
Description
When pasting a <style> tag from the clipboard into a rich text editor, the CSS sanitizer incorrectly rewrites a @namespace rule. This could allow for injection into certain types of websites resulting in data exfiltration.
References
#CVE-2019-17017: Type Confusion in XPCVariant.cpp
- Reporter
- bo13oy
- Impact
- high
Description
Due to a missing case handling object types, a type confusion vulnerability could occur, resulting in a crash. We presume that with enough effort that it could be exploited to run arbitrary code.
References
#CVE-2019-17018: Windows Keyboard in Private Browsing Mode may retain word suggestions
- Reporter
- Siye Lui
- Impact
- moderate
Description
When in Private Browsing Mode on Windows 10, the Windows keyboard may retain word suggestions to improve the accuracy of the keyboard.
References
#CVE-2019-17019: Python files could be inadvertently executed upon opening a download
- Reporter
- Prithwish Kumar Pal
- Impact
- moderate
Description
When Python was installed on Windows, a python file being served with the MIME type of text/plain could be executed by Python instead of being opened as a text file when the Open option was selected upon download.
Note: this issue only occurs on Windows. Other operating systems are unaffected.
Firefox 72.0.2
References
#CVE-2019-17020: Content Security Policy not applied to XSL stylesheets applied to XML documents
- Reporter
- Matthew Somerville
- Impact
- moderate
Description
If an XML file is served with a Content Security Policy and the XML file includes an XSL stylesheet, the Content Security Policy will not be applied to the contents of the XSL stylesheet. If the XSL sheet e.g. includes JavaScript, it would bypass any of the restrictions of the Content Security Policy applied to the XML document.
References
#CVE-2019-17021: Heap address disclosure in parent process during content process initialization on Windows
- Reporter
- Thomas Imbert
- Impact
- moderate
Description
During the initialization of a new content process, a race condition occurs that can allow a content process to disclose heap addresses from the parent process.
Note: this issue only occurs on Windows. Other operating systems are unaffected.
References
#CVE-2019-17022: CSS sanitization does not escape HTML tags
- Reporter
- Michał Bentkowski
- Impact
- moderate
Description
When pasting a <style> tag from the clipboard into a rich text editor, the CSS sanitizer does not escape < and > characters. Because the resulting string is pasted directly into the text node of the element this does not result in a direct injection into the webpage; however, if a webpage subsequently copies the node's innerHTML, assigning it to another innerHTML, this would result in an XSS vulnerability. Two WYSIWYG editors were identified with this behavior, more may exist.
References
#CVE-2019-17023: NSS may negotiate TLS 1.2 or below after a TLS 1.3 HelloRetryRequest had been sent
- Reporter
- Google oss-fuzz
- Impact
- low
Description
After a HelloRetryRequest has been sent, the client may negotiate a lower protocol that TLS 1.3, resulting in an invalid state transition in the TLS State Machine. If the client gets into this state, incoming Application Data records will be ignored.
References
#CVE-2019-17024: Memory safety bugs fixed in Firefox 72 and Firefox ESR 68.4
- Reporter
- Mozilla developers
- Impact
- high
Description
Mozilla developers Jason Kratzer, Christian Holler, and Bob Clary reported memory safety bugs present in Firefox 71 and Firefox ESR 68.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
References
#CVE-2019-17025: Memory safety bugs fixed in Firefox 72
- Reporter
- Mozilla developers
- Impact
- high
Description
Firefox 72 Issues
Mozilla developers Karl Tomlinson, Jason Kratzer, Tyson Smith, Jon Coppeard, and Christian Holler reported memory safety bugs present in Firefox 71. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.