Sourced from waitress's changelog.

2.1.2

Bugfix

- When expose_tracebacks is enabled waitress would fail to properly encode
  unicode thereby causing another error during error handling. See
  https://github.com/Pylons/waitress/pull/378

Header length checking had a calculation that was done incorrectly when the
data was received across multple socket reads. This calculation has been
corrected, and no longer will Waitress send back a 413 Request Entity Too
Large. See Pylons/waitress#376

Security Bugfix

• in 2.1.0 a new feature was introduced that allowed the WSGI thread to start sending data to the socket. However this introduced a race condition whereby a socket may be closed in the sending thread while the main thread is about to call select() therey causing the entire application to be taken down. Waitress will no longer close the socket in the WSGI thread, instead waking up the main thread to cleanup. See Pylons/waitress#377

2.1.1

Security Bugfix

- Waitress now validates that chunked encoding extensions are valid, and don't
  contain invalid characters that are not allowed. They are still skipped/not
  processed, but if they contain invalid data we no longer continue in and
  return a 400 Bad Request. This stops potential HTTP desync/HTTP request
  smuggling. Thanks to Zhang Zeyu for reporting this issue. See
  https://github.com/Pylons/waitress/security/advisories/GHSA-4f7p-27jc-3c36


Waitress now validates that the chunk length is only valid hex digits when
parsing chunked encoding, and values such as 0x01 and +01 are no
longer supported. This stops potential HTTP desync/HTTP request smuggling.
Thanks to Zhang Zeyu for reporting this issue. See
GHSA-4f7p-27jc-3c36


Waitress now validates that the Content-Length sent by a remote contains only
digits in accordance with RFC7230 and will return a 400 Bad Request when the
Content-Length header contains invalid data, such as +10 which would
previously get parsed as 10 and accepted. This stops potential HTTP
desync/HTTP request smuggling Thanks to Zhang Zeyu for reporting this issue. See
GHSA-4f7p-27jc-3c36
</tr></table>

... (truncated)

• 0aa4879 Remove change of default for clear_untrusted_proxy_headers
• 2784628 Revert "Merge pull request #370 from Yourun-proger/del_warnings"
• 479df63 Prep 2.1.2
• 4f6789b Merge pull request #377 from Pylons/bugfix/select-closed-socket-race
• 1952050 Merge pull request #379 from Pylons/enhancement/pyupgrade-3.7
• 8f5b473 pyupgrade 3.7
• c7a3d7e Only close socket in the main thread
• 7c3739b Merge pull request #376 from Pylons/bugfix/header-calculation
• 3066fdd Merge pull request #378 from Pylons/bugfix/expose_tracebacks-encode-error
• 4467d76 Fix tests to assume body is bytes
• Additional commits viewable in compare view

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