Changelog - 2024

23.0.0 - 2024-08-10

minor docs fixes (:pr:`3217`, :pr:`3089`, :pr:`3167`)
worker_class parameter accepts a class (:pr:`3079`)
fix deadlock if request terminated during chunked parsing (:pr:`2688`)
permit receiving Transfer-Encodings: compress, deflate, gzip (:pr:`3261`)
permit Transfer-Encoding headers specifying multiple encodings. note: no parameters, still (:pr:`3261`)
sdist generation now explicitly excludes sphinx build folder (:pr:`3257`)
decode bytes-typed status (as can be passed by gevent) as utf-8 instead of raising TypeError (:pr:`2336`)
raise correct Exception when encounting invalid chunked requests (:pr:`3258`)
the SCRIPT_NAME and PATH_INFO headers, when received from allowed forwarders, are no longer restricted for containing an underscore (:pr:`3192`)
include IPv6 loopback address [::1] in default for :ref:`forwarded-allow-ips` and :ref:`proxy-allow-ips` (:pr:`3192`)

** NOTE **

The SCRIPT_NAME change mitigates a regression that appeared first in the 22.0.0 release
Review your :ref:`forwarded-allow-ips` setting if you are still not seeing the SCRIPT_NAME transmitted
Review your :ref:`forwarder-headers` setting if you are missing headers after upgrading from a version prior to 22.0.0

** Breaking changes **

refuse requests where the uri field is empty (:pr:`3255`)
refuse requests with invalid CR/LR/NUL in heade field values (:pr:`3253`)
remove temporary --tolerate-dangerous-framing switch from 22.0 (:pr:`3260`)
If any of the breaking changes affect you, be aware that now refused requests can post a security problem, especially so in setups involving request pipe-lining and/or proxies.

use utime to notify workers liveness
migrate setup to pyproject.toml
fix numerous security vulnerabilities in HTTP parser (closing some request smuggling vectors)
parsing additional requests is no longer attempted past unsupported request framing
on HTTP versions < 1.1 support for chunked transfer is refused (only used in exploits)
requests conflicting configured or passed SCRIPT_NAME now produce a verbose error
Trailer fields are no longer inspected for headers indicating secure scheme
support Python 3.12

** Breaking changes **

minimum version is Python 3.7
the limitations on valid characters in the HTTP method have been bounded to Internet Standards
requests specifying unsupported transfer coding (order) are refused by default (rare)
HTTP methods are no longer casefolded by default (IANA method registry contains none affected)
HTTP methods containing the number sign (#) are no longer accepted by default (rare)
HTTP versions < 1.0 or >= 2.0 are no longer accepted by default (rare, only HTTP/1.1 is supported)
HTTP versions consisting of multiple digits or containing a prefix/suffix are no longer accepted
HTTP header field names Gunicorn cannot safely map to variables are silently dropped, as in other software
HTTP headers with empty field name are refused by default (no legitimate use cases, used in exploits)
requests with both Transfer-Encoding and Content-Length are refused by default (such a message might indicate an attempt to perform request smuggling)
empty transfer codings are no longer permitted (reportedly seen with really old & broken proxies)

** SECURITY **