Mozilla Firefox Version 51.0 Released with Critical Security Updates

Mozilla sent Firefox Version 51.0 to the release channel today.  The update includes five (5) Critical, six (6) High, ten (10) Moderate and three (3) Low updates.  No additional changes are indicated in the release notes. 

Firefox ESR was updated to version 45.7.0.

The next scheduled release is March 7, 2017 (5 week cycle with release for critical fixes as needed).

26JAN2017 Update Note:   Firefox Version 51.0.1 was released .  From the Release Notes

• Geolocation not working on Windows (Bug 1333516)
• Multiprocess incompatibility did not correctly register with some add-ons (Bug 1333423)

Security Fixes:

Critical

• #CVE-2017-5375: Excessive JIT code allocation allows bypass of ASLR and DEP
• #CVE-2017-5376: Use-after-free in XSL
• #CVE-2017-5377: Memory corruption with transforms to create gradients in Skia
• #CVE-2017-5374: Memory safety bugs fixed in Firefox 51
  Memory safety bugs fixed in Firefox 51
• #CVE-2017-5373: Memory safety bugs fixed in Firefox 51 and Firefox ESR 45.7
  Memory safety bugs fixed in Firefox 51 and Firefox ESR 45.7

High

• #CVE-2017-5378: Pointer and frame data leakage of Javascript objects
• #CVE-2017-5379: Use-after-free in Web Animations
• #CVE-2017-5380: Potential use-after-free during DOM manipulations
• #CVE-2017-5390: Insecure communication methods in Developer Tools JSON viewer
• #CVE-2017-5389: WebExtensions can install additional add-ons via modified host requests
• #CVE-2017-5396: Use-after-free with Media Decoder

Moderate

• #CVE-2017-5381: Certificate Viewer exporting can be used to navigate and save to arbitrary filesystem locations
• #CVE-2017-5382: Feed preview can expose privileged content errors and exceptions
• #CVE-2017-5383: Location bar spoofing with unicode characters
• #CVE-2017-5384: Information disclosure via Proxy Auto-Config (PAC)
• #CVE-2017-5385: Data sent in multipart channels ignores referrer-policy response headers
• #CVE-2017-5386: WebExtensions can use data: protocol to affect other extensions
• #CVE-2017-5394: Android location bar spoofing using fullscreen and JavaScript events
• #CVE-2017-5391: Content about: pages can load privileged about: pages
• #CVE-2017-5392: Weak references using multiple threads on weak proxy objects lead to unsafe memory usage
• #CVE-2017-5393: Remove addons.mozilla.org CDN from whitelist for mozAddonManager

Low

• #CVE-2017-5395: Android location bar spoofing during scrolling
• #CVE-2017-5387: Disclosure of local file existence through TRACK tag error messages
• #CVE-2017-5388: WebRTC can be used to generate a large amount of UDP traffic for DDOS attacks

New

• Users can view passwords in the save password prompt before saving them
  
• Added a zoom button in the URL bar:
  
  • Displays percent above or below 100 percent when a user has changed the page zoom setting from the default
  • Lets users return to the default setting by clicking on the button
• Improved video performance for users without GPU acceleration for less CPU usage and a better full screen experience
  
• Firefox will save passwords even in forms that do not have “submit” events
  
• Added support for FLAC (Free Lossless Audio Codec) playback
  
• Added support for WebGL 2, with advanced graphics rendering features like transform feedback, improved texturing capabilities, and a new sophisticated shading language
  
• A warning is displayed when a login page does not have a secure connection
  
• Added Georgian (ka) and Kabyle (kab) locales
  
• An even faster E10s! Tab Switching is better!
  
• Improved reliability of browser data sync
  
• Remove Belarusian (be) locale
  

Changed

• Updated to NSS 3.28.1
  
• Use 2D graphics library (Skia) for content rendering on Linux
  
• Re-enabled E10s support for Russian (ru) locale
  

Update

To get the update now, select "Help" from the Firefox menu, then pick "About Firefox."  Mac users need to select "About Firefox" from the Firefox menu. If you do not use the English language version, Fully Localized Versions are available for download.

References

• Common questions after updating Firefox
• Security vulnerabilities fixed in Firefox 51
• Mozilla Firefox Release Notes
• Bug Fixes  
• Rapid Release Calendar

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