v25.0.0: Gunicorn 25.0.0

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New Features

• Dirty Arbiters: Separate process pool for executing long-running, blocking
  operations (AI model loading, heavy computation) without blocking HTTP workers
  (PR #​3460)

  • Inspired by Erlang's dirty schedulers
  • Asyncio-based with Unix socket IPC
  • Stateful workers that persist loaded resources
  • New settings: --dirty-app, --dirty-workers, --dirty-timeout,
    --dirty-threads, --dirty-graceful-timeout
  • Lifecycle hooks: on_dirty_starting, dirty_post_fork,
    dirty_worker_init, dirty_worker_exit

• Per-App Worker Allocation for Dirty Arbiters: Control how many dirty workers
  load each app for memory optimization with heavy models
  (PR #​3473)

  • Set workers class attribute on DirtyApp (e.g., workers = 2)
  • Or use config format module:class:N (e.g., myapp:HeavyModel:2)
  • Requests automatically routed to workers with the target app
  • New exception DirtyNoWorkersAvailableError for graceful error handling
  • Example: 8 workers × 10GB model = 80GB → with workers=2: 20GB (75% savings)

• HTTP/2 Support (Beta): Native HTTP/2 (RFC 7540) support for improved performance
  with modern clients (PR #​3468)

  • Multiplexed streams over a single connection
  • Header compression (HPACK)
  • Flow control and stream prioritization
  • Works with gthread, gevent, and ASGI workers
  • New settings: --http-protocols, --http2-max-concurrent-streams,
    --http2-initial-window-size, --http2-max-frame-size, --http2-max-header-list-size
  • Requires SSL/TLS and h2 library: pip install gunicorn[http2]
  • New example: examples/http2_gevent/ with Docker and tests

• HTTP 103 Early Hints: Support for RFC 8297 Early Hints to enable browsers to
  preload resources before the final response
  (PR #​3468)

  • WSGI: environ['wsgi.early_hints'](headers) callback
  • ASGI: http.response.informational message type
  • Works with both HTTP/1.1 and HTTP/2

• uWSGI Protocol for ASGI Worker: The ASGI worker now supports receiving requests
  via the uWSGI binary protocol from nginx
  (PR #​3467)

Bug Fixes

• Fix HTTP/2 ALPN negotiation for gevent and eventlet workers when
  do_handshake_on_connect is False (the default). The TLS handshake is now
  explicitly performed before checking selected_alpn_protocol().

• Fix setproctitle initialization with systemd socket activation
  (#​3465)

• Fix Expect: 100-continue handling: ignore the header for HTTP/1.0 requests
  since 100-continue is only valid for HTTP/1.1+
  (PR #​3463)

• Fix missing _expected_100_continue attribute in UWSGIRequest

• Disable setproctitle on macOS to prevent segfaults during process title updates

• Publish full exception traceback when the application fails to load
  (#​3462)

• Fix ASGI: quick shutdown on SIGINT/SIGQUIT, graceful on SIGTERM

Deprecations

• Eventlet Worker: The eventlet worker is deprecated and will be removed in
  Gunicorn 26.0. Eventlet itself is no longer actively maintained.
  Please migrate to gevent, gthread, or another supported worker type.

Changes

• Remove obsolete Makefile targets
  (PR #​3471)
• Replace RST with markdown documentation format

v24.1.1

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Bug Fixes

• Fix forwarded_allow_ips and proxy_allow_ips to remain as strings for backward
  compatibility with external tools like uvicorn. Network validation now uses strict
  mode to detect invalid CIDR notation (e.g., 192.168.1.1/24 where host bits are set)
  (#​3458,
  PR #​3459)

Full Changelog: benoitc/gunicorn@24.1.0...24.1.1

v24.1.0: Gunicorn 24.1.0

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New Features

• Official Docker Image: Gunicorn now publishes official Docker images to GitHub Container Registry (PR #​3454)

  • Available at ghcr.io/benoitc/gunicorn
  • Based on Python 3.12 slim image
  • Uses recommended worker formula (2 × CPU + 1)
  • Configurable via environment variables

• PROXY Protocol v2 Support: Extended PROXY protocol implementation to support the binary v2 format in addition to the existing text-based v1 format (PR #​3451)

  • New --proxy-protocol modes: off, v1, v2, auto
  • auto mode (default when enabled) detects v1 or v2 automatically
  • v2 binary format is more efficient and supports additional metadata
  • Works with HAProxy, AWS NLB/ALB, and other PROXY protocol v2 sources

• CIDR Network Support: --forwarded-allow-ips and --proxy-allow-from now accept CIDR notation (e.g., 192.168.0.0/16) for specifying trusted networks (PR #​3449)

• Socket Backlog Metric: New gunicorn.socket.backlog gauge metric reports the current socket backlog size on Linux systems (PR #​3450)

• InotifyReloader Enhancement: The inotify-based reloader now watches newly imported modules, not just those loaded at startup (PR #​3447)

Bug Fixes

• Fix signal handling regression where SIGCLD alias caused "Unhandled signal: cld" errors on Linux when workers fail during boot (#​3453)
• Fix socket blocking mode on keepalive connections preventing SSL handshake failures with async workers (PR #​3452)
• Use smaller buffer size in finish_body() for faster timeout detection on slow or abandoned connections (PR #​3453)
• Handle SSLWantReadError in finish_body() to prevent worker hangs during SSL renegotiation (PR #​3448)
• Log SIGTERM as info level instead of warning to reduce noise in orchestrated environments (PR #​3446)
• Print exception details to stderr when worker fails to boot (PR #​3443)
• Fix unreader.unread() to prepend data to buffer instead of appending (PR #​3442)
• Prevent RecursionError when pickling Config objects (PR #​3441)
• Use proper exception chaining with raise from in glogging.py (PR #​3440)

Installation

pip install gunicorn==24.1.0

Or use the official Docker image:

docker pull ghcr.io/benoitc/gunicorn:24.1.0

v24.0.0

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New Features

• ASGI Worker (Beta): Native asyncio-based ASGI support for running async Python frameworks like FastAPI, Starlette, and Quart without external dependencies

  • HTTP/1.1 with keepalive connections
  • WebSocket support
  • Lifespan protocol for startup/shutdown hooks
  • Optional uvloop for improved performance

• uWSGI Binary Protocol: Support for receiving requests from nginx via uwsgi_pass directive

• Documentation Migration: Migrated to MkDocs with Material theme

Security

• eventlet: Require eventlet >= 0.40.3 (CVE-2021-21419, CVE-2025-58068)
• gevent: Require gevent >= 24.10.1 (CVE-2023-41419, CVE-2024-3219)
• tornado: Require tornado >= 6.5.0 (CVE-2025-47287)

Install

pip install gunicorn==24.0.0

v23.0.0

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Gunicorn 23.0.0 has been released. This version improve HTTP 1.1. support and which improve safety

You're invited to upgrade asap your own installation.

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.

Fix CVE-2024-1135

v22.0.0: Gunicorn 22.0 has been released

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Gunicorn 22.0.0 has been released. This version fix the numerous security vulnerabilities. You're invited to upgrade asap your own installation.

Changes:

22.0.0 - 2024-04-17
===================

- 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 **

- fix CVE-2024-1135

1. Documentation is available there: https://docs.gunicorn.org/en/stable/news.html
2. Packages: https://pypi.org/project/gunicorn/

v21.2.0: Gunicorn 21.2.0 has been released

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Gunicorn 21.2.0 has been released. This version fix the issue introduced in the threaded worker.

Changes:

21.2.0 - 2023-07-19
===================
fix thread worker: revert change considering connection as idle .

*** NOTE ***

This is fixing the bad file description error.

1. Documentation is available there: https://docs.gunicorn.org/en/stable/news.html
2. Packages: https://pypi.org/project/gunicorn/

v21.1.0: Gunicorn 21.1.0 has been released

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gunicorn 21.1.0 has been released. This version fix the issue introduced in the threaded worker.

21.1.0 - 2023-07-18

• fix thread worker: fix socket removal from the queuet checkout 21.x

v21.0.1: Gunicorn 21 has been released

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Gunicorn 21 is out with miscellaneous changes. Enjoy!

We made this release major to start our new release cycle. More info will be provided on our discussion forum.

21.0.1 - 2023-07-17

fix documentation build

21.0.0 - 2023-07-17

support python 3.11
fix gevent and eventlet workers
fix threads support (gththread): improve performance and unblock requests
SSL: noaw use SSLContext object
HTTP parser: miscellaneous fixes
remove unecessary setuid calls
fix testing
improve logging
miscellaneous fixes to core engine

Full Changelog: benoitc/gunicorn@21.0.0...21.0.1

v21.0.0

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v20.1.0

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• document WEB_CONCURRENCY is set by, at least, Heroku
• capture peername from accept: Avoid calls to getpeername by capturing the peer name returned by
  accept
• log a warning when a worker was terminated due to a signal
• fix tornado usage with latest versions of Django
• add support for python -m gunicorn
• fix systemd socket activation example
• allows to set wsgi application in configg file using wsgi_app
• document --timeout = 0
• always close a connection when the number of requests exceeds the max requests
• Disable keepalive during graceful shutdown
• kill tasks in the gthread workers during upgrade
• fix latency in gevent worker when accepting new requests
• fix file watcher: handle errors when new worker reboot and ensure the list of files is kept
• document the default name and path of the configuration file
• document how variable impact configuration
• document the $PORT environment variable
• added milliseconds option to request_time in access_log
• added PIP requirements to be used for example
• remove version from the Server header
• fix sendfile: use socket.sendfile instead of os.sendfile
• reloader: use absolute path to prevent empty to prevent0 InotifyError when a file
  is added to the working directory
• Add --print-config option to print the resolved settings at startup.
• remove the --log-dict-config CLI flag because it never had a working format
  (the logconfig_dict setting in configuration files continues to work)

** Breaking changes **

• minimum version is Python 3.5
• remove version from the Server header

** Documentation **

** Others **

• miscellaneous changes in the code base to be a better citizen with Python 3
• remove dead code
• fix documentation generation