[tor-announce] New stable Tor releases:,, and (with security fixes)

Nick Mathewson nickm at torproject.org
Thu Jul 9 17:26:57 UTC 2020

Hello, everybody!

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Source code for Tor,, and is now available;
you can download the source code from the usual place on the website
-- the download page at  for the latest series, and
https://dist.torproject.org for older series.  Packages should be
available within the next several weeks, with a new Tor Browser around
the end of the month.

These releases fix numerous issues, including a denial-of-service
attack affecting all clients and relays using the NSS library. (If
your Tor is built with OpenSSL, which is the default, you don't need
to worry about this one. But if you're using NSS, you should upgrade.)

Below is the changelog for  You can find the changelogs for
the other stable releases here:


There is also a new alpha release today; that announcement will go to
the tor-talk mailing list, as usual.

Changes in version - 2020-07-09
  Tor backports several bugfixes from later releases, including
  some affecting usability.

  This release also fixes TROVE-2020-001, a medium-severity denial of
  service vulnerability affecting all versions of Tor when compiled with
  the NSS encryption library. (This is not the default configuration.)
  Using this vulnerability, an attacker could cause an affected Tor
  instance to crash remotely. This issue is also tracked as CVE-2020-
  15572. Anybody running a version of Tor built with the NSS library
  should upgrade to,,, or
  or later.

  o Major bugfixes (NSS, security, backport from
    - Fix a crash due to an out-of-bound memory access when Tor is
      compiled with NSS support. Fixes bug 33119; bugfix on This issue is also tracked as TROVE-2020-001
      and CVE-2020-15572.

  o Minor bugfix (CI, Windows, backport from
    - Use the correct 64-bit printf format when compiling with MINGW on
      Appveyor. Fixes bug 40026; bugfix on

  o Minor bugfixes (client performance, backport from
    - Resume use of preemptively-built circuits when UseEntryGuards is set
      to 0. We accidentally disabled this feature with that config
      setting, leading to slower load times. Fixes bug 34303; bugfix

  o Minor bugfixes (compiler warnings, backport from
    - Fix a compiler warning on platforms with 32-bit time_t values.
      Fixes bug 40028; bugfix on

  o Minor bugfixes (linux seccomp sandbox, nss, backport from
    - Fix a startup crash when tor is compiled with --enable-nss and
      sandbox support is enabled. Fixes bug 34130; bugfix on Patch by Daniel Pinto.

  o Minor bugfixes (logging, backport from
    - Downgrade a noisy log message that could occur naturally when
      receiving an extrainfo document that we no longer want. Fixes bug
      16016; bugfix on

  o Minor bugfixes (manual page, backport from
    - Update the man page to reflect that MinUptimeHidServDirectoryV2
      defaults to 96 hours. Fixes bug 34299; bugfix on

  o Minor bugfixes (onion service v3, backport from
    - Prevent an assert() that would occur when cleaning the client
      descriptor cache, and attempting to close circuits for a non-
      decrypted descriptor (lacking client authorization). Fixes bug
      33458; bugfix on

  o Minor bugfixes (portability, backport from
    - Fix a portability error in the configure script, where we were
      using "==" instead of "=". Fixes bug 34233; bugfix on

  o Minor bugfixes (relays, backport from
    - Stop advertising incorrect IPv6 ORPorts in relay and bridge
      descriptors, when the IPv6 port was configured as "auto". Fixes
      bug 32588; bugfix on

  o Documentation (backport from
    - Fix several doxygen warnings related to imbalanced groups. Closes
      ticket 34255.

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