Tor Browser 7.0a3 is released

Update (May 8 10:20 UTC): Mozilla released Firefox 52.1.1esr fixing among others a security bug which could lead to a potentially exploitable crash on the Windows platform. By default Tor Browser users are not affected as WebGL is put behind click-to-play placeholders, thanks to NoScript. Nevertheless, we are preparing a release later this week picking this fix up and, in addition to that, a lot of other improvements for our alpha series.

Update (Apr 24 8:36 UTC): Thanks to all for testing this alpha release so far. It turns out there are a number of issues that are affecting a lot of our alpha users. The following list should give an overview and help to avoid duplicate bug reports:

  • Tor Browser is crashing when opening/downloading files that need an external application to handle them. This is bug 21766.
  • Tor Browser is crashing on about:addons with the security slider set to "high" and does not show any preferences on about:preferences ticked. This issue is tracked in bug 21962.
  • The canvas prompt is not shown anymore in Tor Browser. This issue is tracked in bug 21778.
  • There is no sound on Linux systems without PulseAudio anymore. This is bug 1247056. Check this one out for Mozilla's reasoning behind dropping ALSA support.

Tor Browser 7.0a3 is now available from the Tor Browser Project page and also from our distribution directory.

This release features important security updates to Firefox.

This is the first alpha release which is based on Firefox ESR 52. We updated all of our patches that did not get upstreamed yet and made Torbutton and Tor Launcher multiprocess (e10s) compatible. After the first nightly build based on ESR52 went out we already fixed a number of bugs associated with this switch. But more remain, please help!

We hope having e10s and Mozilla's content sandbox enabled will be one of the major new features in the upcoming Tor Browser 7.0 series, both security- and performance-wise. While we are still working on the sandboxing part for Windows, both Linux and macOS have e10s and content sandboxing enabled by default in Tor Browser 7.0a3. There are already a number of bugs related to that on our radar which can be found on our bug tracker and which are tagged with the `tbb-e10s` keyword. If you find more, please report them!

The switch to Firefox ESR 52 raises the system requirements for Tor Browser on Windows and macOS. Computers running Windows and are not SSE2-capable are not supported anymore. On Apple computers with OS X < 10.9 Tor Browser won't run anymore either. Update (Apr 24 8:41 UTC): Only the browser part of Tor Browser is affected by these new constraints. If you are e.g. on Windows and are using the expert bundle or are extracting tor from Tor Browser it should run on any computer it used to run. The same holds for macOS with one exception: tor we ship in Tor Browser won't run on Apple computers with OS X 10.6 anymore either.

We updated our toolchains during the ESR transition as well. In particular we retired the old GCC-based one for our macOS cross-compilation and rely solely on clang/cctools now. As with previous releases building 7.0a3 is fully reproducible on all three supported platforms, even though we needed to deploy a last minute patch for Linux bundles this time.

Apart from switching to the new ESR and dealing with related issues we included a new Tor alpha ( and updated our NoScript (5.0.2) and HTTPS-Everywhere versions (5.2.14). The Sandboxed Tor Browser for Linux got updated to 0.0.6 making sure it is compatible with Firefox ESR 52.

As in Tor Browser 6.5.2 we provide a fix for Tor Browser crashing on on Windows and for Twitter issues that got reported already a while ago. We update our security slider as well taking newer JIT preferences into account.

A note to Windows users: We signed the .exe files with a new codesigning certificate as the old one is about to expire. If there are issues with that new certificate, e.g. scary warnings showing up after downloading a Tor Browser .exe file and double-clicking on it, please let us know.

The full changelog since Tor Browser 7.0a2 is:

  • All Platforms
    • Update Firefox to 52.1.0esr
    • Tor to
    • Update Torbutton to
      • Bug 21865: Update our JIT preferences in the security slider
      • Bug 21747: Make 'New Tor Circuit for this Site' work in ESR52
      • Bug 21745: Fix handling of catch-all circuit
      • Bug 21547: Fix circuit display under e10s
      • Bug 21268: e10s compatibility for New Identity
      • Bug 21267: Remove window resize implementation for now
      • Bug 21201: Make Torbutton multiprocess compatible
      • Translations update
    • Update Tor Launcher to 0.2.12
      • Bug 21920: Don't show locale selection dialog
      • Bug 21546: Mark Tor Launcher as multiprocess compatible
      • Bug 21264: Add a README file
      • Translations update
    • Update HTTPS-Everywhere to 5.2.14
    • Update NoScript to 5.0.2
    • Update sandboxed-tor-browser to 0.0.6
      • Bug 21764: Use bubblewrap's `--die-with-parent` when supported
      • Fix e10s Web Content crash on systems with grsec kernels
      • Bug 21928: Force a reinstall if an existing hardened bundle is present
      • Bug 21929: Remove hardened/ASAN related code
      • Bug 21927: Remove the ability to install/update the hardened bundle
      • Bug 21244: Update the MAR signing key for 7.0
      • Bug 21536: Remove asn's scramblesuit bridge from Tor Browser
      • Add back old MAR signing key to not break updating Tor Browser stable
      • Add `prlimit64` to the firefox system call whitelist
      • Fix compilation with Go 1.8
      • Use Config.Clone() to clone TLS configs when available
    • Update Go to 1.7.5 (bug 21709)
    • Bug 21555+16450: Don't remove Authorization header on subdomains (e.g. Twitter)
    • Bug 21887: Fix broken error pages on higher security levels
    • Bug 21876: Enable e10s by default on all supported platforms
    • Bug 21876: Always use esr policies for e10s
    • Bug 20905: Fix resizing issues after moving to a direct Firefox patch
    • Bug 21875: Modal dialogs are maximized in ESR52 nightly builds
    • Bug 21885: SVG is not disabled in Tor Browser based on ESR52
    • Bug 17334: Hide Referer when leaving a .onion domain (improved patch)
    • Bug 3246: Double-key cookies
    • Bug 8842: Fix XML parsing error
    • Bug 16886: 16886: "Add-on compatibility check dialog" contains Firefox logo
    • Bug 19192: Untrust Blue Coat CA
    • Bug 19955: Avoid confusing warning that favicon load request got cancelled
    • Bug 20005: Backport fixes for memory leaks investigation
    • Bug 20755: is broken in Tor Browser
    • Bug 21896: Commenting on website is broken due to CAPTCHA not being displayed
    • Bug 20680: Rebase Tor Browser patches to 52 ESR
    • Bug 21917: Add new obfs4 bridges
    • Bug 21918: Move meek-amazon to backend
  • Windows
    • Bug 21795: Fix Tor Browser crashing on
    • Bug 12426: Make use of HeapEnableTerminationOnCorruption
    • Bug 19316: Make sure our Windows updates can deal with the SSE2 requirement
    • Bug 21868: Fix build bustage with FIREFOX_52_0_2esr_RELEASE for Windows
  • OS X
    • Bug 21723: Fix inconsistent generation of MOZ_MACBUNDLE_ID
    • Bug 21724: Make Firefox and Tor Browser distinct macOS apps
    • Bug 21931: Backport OSX SetupMacCommandLine updater fixes
    • Bug 15910: Don't download GMPs via the local fallback
  • Linux
    • Bug 21907: Fix runtime error on CentOS 6
    • Bug 21748: Fix broken Snowflake build and update bridge details
    • Bug 21954: Snowflake breaks the 7.0a3 build
    • Bug 15910: Don't download GMPs via the local fallback
  • Build system
    • Windows
      • Bug 21837: Fix reproducibility of accessibility code for Windows
      • Bug 21240: Create patches to fix mingw-w64 compilation of Firefox ESR 52
      • Bug 21904: Bump mingw-w64 commit to help with sandbox compilation
      • Bug 18831: Use own Yasm for Firefox cross-compilation
    • OS X
      • Bug 21328: Updating to clang 3.8.0
      • Bug 21754: Remove old GCC toolchain and macOS SDK
      • Bug 19783: Remove unused macOS helper scripts
      • Bug 10369: Don't use old GCC toolchain anymore for utils
      • Bug 21753: Replace our old GCC toolchain in PT descriptor
      • Bug 18530: ESR52 based Tor Browser only runs on macOS 10.9+
    • Linux
      • Bug 21930: NSS libraries are missing from mar-tools archive
      • Bug 21239: Adapt Linux Firefox descriptor to ESR52 (use GTK2)
      • Bug 21960: Linux bundles based on ESR 52 are not reproducible anymore
      • Bug 21629: Fix broken ASan builds when switching to ESR 52

April 21, 2017


THX alot for all your work! :-)

Unfortunately, the latest TBB (tor-browser-linux64-7.0a3_en-US.tar) crashes immediately when clicking in the addons-page on, for example, 'get-addons' or 'appearance'.
System: Fedora 25, (kernel 4.10.10-200.fc25.x86_64)


April 21, 2017



Report: DOJ Prepares Charges Against WikiLeaks, Assange
Charges could include theft of government property, conspiracy or violations of the Espionage Act


April 21, 2017


SSL Observatory WARN: Failed to initialize NSS component:Error: couldn't find function symbol in library


April 21, 2017


14:29:36.196 TypeError: categories.setAttribute is not a function 1 preferences.js:76:7
init_all/< chrome://browser/content/preferences/in-content/preferences.js:76:7


April 21, 2017


On macOS Sierra, when I open 7.0a3, I get a warning about my window being in full screen, even though it's not in full screen. I have version 6 installed, and I'm opening version 7 directly from the .dmg

You're not supposed to run any of them directly from the DMG:

OK, well, that should definitely be made clear. I was under the assumption it was self-contained and I could run it from anywhere

thanks for the update! great work!

When "Save Link As..."
[04-22 17:46:39] Torbutton INFO: New domain isolation for --unknown--: 58dc48b1e371d4881a82551e1b70600a
[04-22 17:46:39] Torbutton INFO: tor SOCKS: via

Any news regarding Orfox, I.e. TOR browser for android? It hasn't received any updates for several months, which makes me worried about its security. I use it nearly for all my browsing.

nice but I have a question: when I go to the settings I can't mark any options. I only see blank squares but can't mark them when I click on them. why?

I guess you have set the security slider to "high"? In that case you are hitting which we are about to fix.

Yes I have It on "High".. so It is normal? does Tor browser controls that settings by Its own?

No. What you see is kind of collateral damage done by bug 21962. It will be fixed in the next alpha release.

dign the wide window it almost fits this netbook. Now if it could just be nudged north a little :) BTW all is working good here so far...cept ofcourse sound.

18:03:21.677 TypeError: realSpellChecker is null 1 InlineSpellCheckerContent.jsm:55:5

Same issues from 6.5a2 returned, which dcf created ticket #19837 for. dcf said it was about experimenting with #19273.

Thanks for the report. How do I reproduce your problem? I tested with a 7.0a3 on Windows and Linux following the links dcf mentioned in the description of #19837. Both loaded fine for me. Does this happen with a clean and freshly downloaded 7.0a3?

Seems he means SVG elements don't show in AV controls.

I didn't know when comments close so I guess I rushed; I haven't really had the chance to play around with this release yet. I'll try a fresh install in a few days. I used the same wired router to send in our taxes from another machine, and when I connected this one again there were strange requests through ports, Ru malware that kept respawning in different places, drivers & registry keys screwed with, firewall & security software disabled, MBAM not working.It's been a headache that I've been trying to sort out for over a week now. I've had to run a number of system restores and update TB in addition to other programs so I'll just assume for now that that's the likely cause of my issues. I'll let you know if it's still happening after a clean install.Thanks for taking the time to respond.

problem was an extension to an add-on; DTA anti-container. removed it, and now works fine.

Flashgot too

11:42:03.229 Error: Callback received for bad URI: [xpconnect wrapped nsIURI] 1 permissions.js:231:11
onIndexedDBUsageCallback chrome://browser/content/pageinfo/permissions.js:231:11

Nothing. What's the issue with it?

Compare with 6.5.2

I did. It looks the same on my Linux box. So, again, what is the problem you are seeing? And how can I reproduce it?

security slider on medium

Error: Timed out while waiting for data
Stack trace:
NetMonitorView.showNetworkStatisticsView/< chrome://devtools/content/netmonitor/netmonitor-view.js:241:9
TaskImpl.prototype._run resource://devtools/shared/task.js:312:39
Handler.prototype.process resource://gre/modules/Promise-backend.js:935:21
this.PromiseWalker.walkerLoop resource://gre/modules/Promise-backend.js:813:7
this.PromiseWalker.scheduleWalkerLoop/< resource://gre/modules/Promise-backend.js:747:11
A promise chain failed to handle a rejection. Did you forget to '.catch', or did you forget to 'return'?

Date: Wed Apr 26 2017 12:10:18 GMT+0000 (UTC)
Full Message: TypeError: inspector is undefined
Full Stack: nsContextMenu.prototype.inspectNode/<@chrome://browser/content/nsContextMenu.js:576:11
Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:932:23
this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:813:7
this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:747:11

20:16:17.413 A promise chain failed to handle a rejection. Did you forget to '.catch', or did you forget to 'return'?

Date: Wed Apr 26 2017 20:16:10 GMT+0000 (UTC)
Full Message: TypeError: inspector.selection is undefined
Full Stack: nsContextMenu.prototype.inspectNode/<@chrome://browser/content/nsContextMenu.js:576:11
Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:932:23
this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:813:7
this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:747:11
1 nsContextMenu.js:576

15:57:31.795 A promise chain failed to handle a rejection. Did you forget to '.catch', or did you forget to 'return'?

Date: Thu Apr 27 2017 15:57:11 GMT+0000 (UTC)
Full Message: TypeError: elem.ownerGlobal is null
Full Stack: PageInfoListener.getMediaItems@chrome://browser/content/content.js:1164:9
1 content.js:1164

Why is exact TBB version still detectable by the site?

By which site?

Maybe because it is easy to detect that you are using Tor Browser and 7.0a3 is the only one so far using ESR52?

It can't detect version when visiting from Win XP, so I'm a bit worried.

where can i search through tor

Did Cl0udflare change how it handles Tor recently? In the previous alpha release, Cl0udflare-hosted sites seemed to work flawlessly and I rarely had to solve captchas. However, over the past month or two, I've had to contend with the dreaded "Attention Required" page on nearly every site again. It seems like the issues w/ Cl0udflare have gotten worse than they were last year.

I am also seeing fewer captchas recently.

I'm seeing two Tor Browser processes simultaneously in Win Task Manager. Only a single application running, but two firefox.exe *32.[Is this how e10s would appear & would multiprocessing FF be a likely reason why some add-ons are not working as expected?]The second process appears after Tor connects to the network, as the browser is loading, just prior to About:tor displaying as the home page. Right after this, the 2nd process disappears, but comes back the moment I do anything outside of the home page, About:*, or options; if I search, load a locally stored file, or anything else, the 2nd firefox.exe *32 process appears.If I go back to the previous page i.e. the home page, I get a 'Problem Loading Page' tab, & a warning message stating 'The address isn't valid...' If I reload the About:tor page after closing the other tabs then the 2nd firefox.exe * 32 disappears again.[Again, just wondering if this is how Electrolysis child processes appear & if the compatibility of some FF add-ons would be affected.]

Yes, I think you describe the e10s behavior. I am not sure about your add-on issues, though, because Tor Browser, as Firefox is supposed to do, should fall back to e10s being disabled once it encounters an extension that is not compatible with it. But maybe those extensions you have are falling through the cracks? How can I reproduce your problems?

Yes, the issue with going back to about:tor is known: see:

Mozilla solved the problem in Firefox 57, hehe

OK, well the minor issues seemed to be identical to what I experienced in 6.5a2; see: comment tree from Reply #1199 on the 6.5a2 blog post where dcf created ticket #19837.Around a week ago I think my browser's support page said that multiprocess windows were disabled, probably because the add-ons were incompatible with e10s like you described. They're enabled now, and I assume have been since I removed the add-ons last week. They were DTA AntiContainer & Flashgot.Just to be clear, TB seems to be working fine and I only experienced the issue with those particular add-ons installed. I guess I'll just have to wait for the developers of those extensions to re-write them to be compatible with the WebExtensions API.Thank you for your time, gk.

Prefixed WebGL is not disabled?

What do you mean? FWIW: We are still auditing WebGL2 and depending on how it goes we might need to disable all related features. tracks that task.

I mean NoScript disables WebGL (v2 too), but not prefixed version.