Firefox 49.0.2 is out

Martin Brinkmann
Oct 21, 2016

Mozilla has released an update for the stable version of its Firefox web browser that brings the version of it to Firefox 49.0.2.

Firefox 49.0.2 is a bug fix and security release that fixes several issues in the browser, among them two that we talked about just yesterday.

The new version is already available, and users may want to run a manual check for updates to speed up the updating process. This goes especially for users who are affected by one or multiple of the bugs fixed in the new version.

Firefox 49.0.2

Do the following to run a manual update check in Firefox:

  1. Tap on the Alt-key on the computer keyboard, and select Help > About Firefox from the menu.

This should open a small About Mozilla Firefox window on the screen that checks for updates automatically. Firefox should find the version 49.0.2 update for the browser, and either download and install it automatically, or suggest to do so.

The following issues are fixed in the new version: (here is the changelog link)

  1. Asynchronous plugin rendering for Flash is now enabled by default. This addresses performance issues and should reduce crashes when visiting sites that use Flash. (Bug 1307108)
  2. D3D9 fallback disabled if hardware acceleration is used to prevent graphical artifacts on the screen. (Bug 1306465)
  3. Fixed a network bug that prevented some Firefox users from seeing the user interface on start. (Bug 1305436)
  4. Fixed a compatibility issue that affected file uploads. (Bug 1306472)
  5. Fixed another issue affecting Array.prototype.values. (Bug 1299593)
  6. Fixed a canvas filters graphics issue in HTML5 apps. (Bug 1304539)
  7. Changed diagnostic information on timing for tab switching. (Bug 1304113)

Mozilla on top of that fixed several security vulnerabilities in Firefox 49.0.2.

CVE-2016-5287: Crash in nsTArray_base<T>::SwapArrayElements

A potentially exploitable use-after-free crash during actor destruction with service workers. This issue does not affect releases earlier than Firefox 49.

CVE-2016-5288: Web content can read cache entries

A developer demonstrated that web content could access information in the HTTP cache if e10s is disabled. This can reveal some visited URLs and the contents of those pages. This issue affects Firefox 48 and 49.

The Android version has been updated as well to Firefox 49.0.2 for Android. It only got one of the fixes that dealt with compatibility issues with file uploads, and the security fixes.

Now You: Have you been affected by any of the issues?

Firefox 49.0.2 is out
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Firefox 49.0.2 is out
Mozilla has released an update for the stable version of its Firefox web browser that brings the version of it to Firefox 49.0.2.
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  1. El said on November 4, 2016 at 2:50 pm

    49.0.2 a complete failure for me! Webpages won’t load, or partially load. The blue circles just go on and on and sometimes I now get a message that says it’s not a secure website or secure connection failed. Takes 1-4 minutes for a page to load, “if” it loads. I don’t have the time or knowledge to deal with this nonsense. I’m ready to scream. So sorry I updated yesterday.

  2. Josh Taylor said on October 24, 2016 at 11:29 pm

    49.0.2 is causing problems on 8bbit unable to load certain games when it says “Click to Start” when the highlighter on it rather than the hand.

  3. Guest703 said on October 24, 2016 at 10:09 pm

    @Dennis – did you have adequate security? Ublock Origin? Umatrix? Antivirus? HIPS (eg. Online Armor)?, I’m willing to bet that had you had all this security in place, that wouldn’t have happened to you.

  4. Dennis Kinnan` said on October 24, 2016 at 12:47 am

    A complete failure for me. Hacking site took over page download and proceeded to obliviate all my email. Totally wiped out my bookmarks. Attempted to install malware pages all over the place. “Hot Ruby” was on tap. Probably got all of my user name passwords from Last Pass. Wiped out all my addons.

    Oh and yes all this on top of me arriving home from the hopital spaced out on liberal amounts of Oxycontin. What a beautiful world it was!!

    As for Fire Fox 49.0.2 once burned, twice shy!! Give it another month. I might try again. I did however have a fresh copy of a complete backup of my system before it got sodomized. Backing the system up solved the problem…..but Fire Fox 49.0.2 and from other commnets I’ve heard not in a blue moon.

  5. Tom Hawack said on October 22, 2016 at 1:34 pm

    After testing I’ve,

    1- DISABLED Asynchronous Plugin Rendering :
    by reverting “dom.ipc.plugins.asyncdrawing.enabled” from true to false (as before FF49.0.2)
    2- DISABLED D3D9 Acceleration Fallback :
    by accepting “layers.allow-d3d9-fallback.enabled” as true (as from FF49.0.2)

    Enabling Asynchronous Plugin Rendering is problematic here when shifting full-screen on/off, no big deal but the sound and image are “bothered” during that shift, half a second perhaps but annoying.

    All these problems related to the Flash Player rendering. A true pain when HTML5 is swift. When will Adobe’s Flash be definitely abandoned? That’s the first question I’d ask a clairvoyant. “When, O Great Wisdom, tell me : when?”

  6. Jimbo said on October 22, 2016 at 11:50 am

    Thanks Backbutton, I was having the same problem and you just saved me some time.

  7. Alex said on October 22, 2016 at 5:54 am

    I asked in #firefox on freenode and Caspy7 helped me by telling me to try setting “dom.ipc.plugins.asyncdrawing.enabled” to false in about:config. It worked! Now fullscreen buttons on Flash videos do not switch to exclusive fullscreen mode, just as in 49.0.1 and earlier. Anyone who is having fullscreen Flash issues should try this.

  8. bryan said on October 22, 2016 at 5:53 am

    updated to 49.0.2 now every time i click the back button a history drop down menu appears then i have to click somewhere to make it go away. i really dont need people standing near my computer seeing a list of all the sites i have visited.

    1. Tod said on October 23, 2016 at 11:32 pm

      I’m not worried about seeing my history in my case, but the drop down menu not only blocks part of whatever page I’m looking at, but takes mouse focus so I have to click on the page before I can mouse-scroll.

  9. Anonymous said on October 22, 2016 at 5:40 am

    With the Firefox portables versions (Esr & stable) and the Flash plugin installed in PortableApps/CommonFiles it worked fine until now. Today i have to install Flash otherwise the plugin is trying to load indefinitely with no success. With Pale Moon and the Flash plugin just puted in its browser’s folder no problem even with the 64 bit version. Never had this problem before, thanks Mozilla.

  10. Alex said on October 22, 2016 at 5:24 am

    I asked in #firefox on freenode and Caspy7 helped me by telling me to try setting “dom.ipc.plugins.asyncdrawing.enabled” to false in about:config. It worked! Anyone who is having fullscreen Flash issues should try this.

  11. Backbutton said on October 22, 2016 at 2:25 am

    After updating I started having a problem with the back button, it showed the history underneath it. Very annoying but after some testing with my add ons it seemed the update V1.75 from Better Privacy was causing this problem. Checked Mozillas website and yes, the maker of BetterPrivacy had already posted a small prob with the new version and promised a fast fix.

    Maybe this helps some people who might be scratching their heads if they run into the same problem.

    1. gmon said on October 22, 2016 at 7:27 pm

      Thanks for affirming that I am not alone since I couldn’t find any reference to this problem, now waiting for the fix from Better Privacy

  12. Chip Telse said on October 21, 2016 at 6:46 pm

    49.0.2 causes all types of issues with flash when I switch to full screen on a multiple monitor setup. Long delay / blank black screen (on multiple displays) / redraw and I lose a bottom anchored app (stardock) on the second monitor when it switches back from fullscreen.

    1. Tony said on October 21, 2016 at 7:52 pm

      To help the Mozilla team and improve Firefox, report all Firefox bugs on Bugzilla:

  13. Bolenath said on October 21, 2016 at 6:34 pm

    @Tamil Check uBlock or uMatrix, surely they have a way to stop videos from loading.

    1. coakl said on October 26, 2016 at 12:41 am

      NoScript blocks HTML5 video, if you go to: NoScript Options, Advanced, Embeddings
      And checkmark the Video tag.

  14. Tom Hawack said on October 21, 2016 at 1:17 pm

    Tamil, there is a script available at Greasyfork, I haven’t tried it :
    Pause all HTML5 videos on load –

    I guess you know that but in case you don’t : you’ll need a “javascript manager” such as the Greasemonkey add-on to run such a script.

  15. Tom Hawack said on October 21, 2016 at 11:05 am

    I have updated Firefox to 49.0.2 but I’ve never experienced issues, with Flash included, described as fixed with the update. In fact I’ve never had Firefox crash, as far as I can remember. Flash videos display as with Firefox 49.0.1, no problems unless what seems inherent to Flash when not played in wmode=direct which is a tiny halt when switching to fullscreen and back. The wmode=direct could be applied on previous versions of Flash Player / previous versions of Firefox by means of a dedicated add-on or javascript, but no longer. I say “previous versions” referring to August 2015, after which I removed Flash… before reinstalling it two weeks ago.

    I definitely prefer HTML5 video rendering, much smoother. Unfortunately some major websites just won’t play the game of progress.

    1. Martin Brinkmann said on October 21, 2016 at 11:31 am

      Tom, I have never experienced the described issues myself either. I prefer HTML5 over Flash any time of the day, and don’t have Flash installed in Firefox anymore. If there is a site that only uses Flash, I either switch to Chrome if I really need to access the site, or simply close it and don’t look back.

      1. Jerry said on October 24, 2016 at 2:44 am

        > this blocks auto-play, but the video is still buffered.
        Ok I understand. I know no browser add-on to stop HTML5 audio/video buffering. And it is strange that is not natively available.

        I wrote a code on my online filetype player at to stop buffering. (Tested on Firefox and Chromium)

        Play the first WebM video and click on “Stop video buffering”. The video buffering will stop immediately. It is not very nice but it works! So I think it is possible to create a browser add-on for all sites ;)

      2. Jerry said on October 21, 2016 at 9:03 pm

        @Tamil Chola:
        > Is there a way to stop html5 videos from auto-loading?
        about:config –> media.autoplay.enabled –> false

      3. Martin Brinkmann said on October 22, 2016 at 8:22 am

        Jerry, this blocks auto-play, but the video is still buffered.

      4. Tamil Chola said on October 21, 2016 at 12:38 pm

        Is there a way to stop html5 videos from auto-loading?
        I tried flashblock extension it pauses html5 but video stills cached by browser. Same story with chrome. bandwidth is my concern.

      5. Martin Brinkmann said on October 21, 2016 at 1:02 pm

        No, not that I know of.

      6. Tom Hawack said on October 21, 2016 at 11:52 am

        Perhaps running Flash videos only on a browser such as Chrome which handles PPAPI and avoiding the NPAPI plug-in is wiser. PPAPI on Firefox is scheduled I think, looking forwards to that. In fact looking forwards to the time Flash will be definitely buried.

        I hesitated to re-install Flash as a plug-in (only) and I haven’t got the Chrome browser installed. No bashing but I won’t install a browser for the sole purpose of accessing to PPAPI rendered Flash. Other topic.

        I take precautions with the NPAPI Flash plug-in. I’ve edited its mms.cfg file and I’ll never-ever install the activeX version of Flash. At this time, just because less than five sites I care for require Adobe’s Flash and refuse HTML5 (refusing to the point of not answering my dedicated emails) I’ve surrendered in a way and taking conscious of this does not make my days. C’est la vie…

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