Description
Gunicorn fails to properly validate Transfer-Encoding headers, leading to HTTP Request Smuggling (HRS) vulnerabilities. By crafting requests with conflicting Transfer-Encoding headers, attackers can bypass security restrictions and access restricted endpoints. This issue is due to Gunicorn's handling of Transfer-Encoding headers, where it incorrectly processes requests with multiple, conflicting Transfer-Encoding headers, treating them as chunked regardless of the final encoding specified. This vulnerability allows for a range of attacks including cache poisoning, session manipulation, and data exposure.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| benoitc | benoitc/gunicorn | unspecified – ≤ latest | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | gunicorn | 22.0.0-1 | — |
| Debian 13 | gunicorn | 22.0.0-1 | — |
| Debian 12 | gunicorn | 20.1.0-6+deb12u1 | — |
| Debian 11 | gunicorn | 20.1.0-1+deb11u1 | DLA-3996-1 |
| Debian 10 | gunicorn | 19.9.0-1+deb10u1 | DLA-3851-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | gunicorn | No fix yet | — |
| Ubuntu 26.04 LTS | gunicorn | No fix yet | — |
| Ubuntu 25.10 | gunicorn | No fix yet | — |
| Ubuntu 24.04 LTS | gunicorn | No fix yet | — |
| Ubuntu 22.04 LTS | gunicorn | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | gunicorn | No fix yet | — |
| Ubuntu 18.04 LTS | gunicorn | No fix yet | — |
| Ubuntu 16.04 LTS | gunicorn | No fix yet | — |
| Ubuntu Pro 14.04 LTS | gunicorn | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Satellite Capsule 6 | python-cryptography +1 | 42.0.8-1.el8pc | RHSA-2024:7987 |
| Red Hat Satellite Capsule 6 | python-django +1 | 4.2.15-1.el8pc | RHSA-2024:7987 |
| Red Hat Satellite Capsule 6 | python-gunicorn +1 | 22.0.0-1.el8pc | RHSA-2024:7987 |
| Red Hat Satellite 6 | python-cryptography +1 | 42.0.8-1.el8pc | RHSA-2024:7987 |
| Red Hat Satellite 6 | python-django +1 | 4.2.15-1.el8pc | RHSA-2024:7987 |
| Red Hat Satellite 6 | python-gunicorn +1 | 22.0.0-1.el8pc | RHSA-2024:7987 |
| Red Hat Satellite 6 | rubygem-foreman_theme_satellite | 13.3.0-0.1.el8sat | RHSA-2024:7987 |
| Red Hat Satellite 6 | yggdrasil-worker-forwarder | 0.0.3-2.el8sat | RHSA-2024:7987 |
| Red Hat Rhui 4 | python-aiohttp +1 | 3.9.4-1.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-cryptography +1 | 42.0.8-1.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-django +1 | 4.2.15-1.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-grpcio +1 | 1.65.4-1.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-gunicorn +1 | 22.0.0-1.0.1.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-jinja2 +1 | 3.1.4-1.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-requests +1 | 2.32.3-2.el8ui | RHSA-2025:1335 |
| Red Hat Rhui 4 | python-sqlparse +1 | 0.5.0-1.el8ui | RHSA-2025:1335 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat OpenStack 17 | python-gunicorn +1 | 20.0.4-7.el9ost | RHSA-2024:2727 |
| Red Hat OpenStack 16 | python-gunicorn +1 | 19.9.0-11.el8ost | RHSA-2024:4054 |
| Red Hat Ansible Automation Platform Inside 2 | python-black +1 | 22.8.0-2.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Inside 2 | python-cryptography +1 | 42.0.5-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Inside 2 | python-jinja2 +1 | 3.1.4-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Inside 2 | python39-black +1 | 22.8.0-2.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Inside 2 | python39-cryptography +1 | 42.0.5-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Inside 2 | python39-jinja2 +1 | 3.1.4-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Inside 2 | receptor +1 | 1.4.8-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python-black +1 | 22.8.0-2.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python-cryptography +1 | 42.0.5-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python-idna +1 | 3.7-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python-jinja2 +1 | 3.1.4-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python-requests +1 | 2.32.2-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python39-black +1 | 22.8.0-2.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python39-cryptography +1 | 42.0.5-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python39-idna +1 | 3.7-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python39-jinja2 +1 | 3.1.4-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | python39-requests +1 | 2.32.2-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform Developer 2 | receptor +1 | 1.4.8-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | automation-controller-venv-tower | 4.5.7-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | automation-hub +2 | 4.9.2-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-aiohttp +1 | 3.9.5-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-black +1 | 22.8.0-2.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-cryptography +1 | 42.0.5-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-galaxy-ng +1 | 4.9.2-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-gunicorn +1 | 22.0.0-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-idna +1 | 3.7-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-jinja2 +1 | 3.1.4-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-pillow +1 | 10.3.0-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-pydantic +1 | 1.10.15-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-requests +1 | 2.32.2-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-social-auth-app-django +1 | 5.4.1-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python-sqlparse +1 | 0.5.0-1.el9ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-aiohttp +1 | 3.9.5-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-black +1 | 22.8.0-2.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-cryptography +1 | 42.0.5-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-gunicorn +1 | 22.0.0-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-idna +1 | 3.7-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-jinja2 +1 | 3.1.4-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-pillow +1 | 10.3.0-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-pydantic +1 | 1.10.15-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-requests +1 | 2.32.2-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-social-auth-app-django +1 | 5.4.1-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | python39-sqlparse +1 | 0.5.0-1.el8ap | RHSA-2024:3781 |
| Red Hat Ansible Automation Platform 2 | receptor +1 | 1.4.8-1.el8ap | RHSA-2024:3781 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | python-gunicorn | 19.7.1-150000.3.7.1 | SUSE-SU-2024:2881-1 |
| SLES 15 SP5 | python-gunicorn | 19.7.1-150000.3.7.1 | SUSE-SU-2024:2881-1 |
| SLES 15 SP4 | python-gunicorn | 19.7.1-150000.3.7.1 | SUSE-SU-2024:2881-1, SUSE-SU-2024:1440-1 |
| SLES 15 SP3 | python-gunicorn | 19.7.1-150000.3.7.1 | SUSE-SU-2024:2881-1 |
| SLES 15 SP2 | python-gunicorn | 19.7.1-150000.3.7.1 | SUSE-SU-2024:2881-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 3 | python-gunicorn | 20.1.0-150400.12.6.1 | SUSE-SU-2024:1440-1 |
| SLES for SAP 15 SP4 | python-gunicorn | 20.1.0-150400.12.6.1 | SUSE-SU-2024:1440-1 |
| SLE HPC 15 SP4 | python-gunicorn | 20.1.0-150400.12.6.1 | SUSE-SU-2024:1440-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.5 | python-gunicorn | 19.7.1-150000.3.7.1 | SUSE-SU-2024:2881-1, SUSE-SU-2024:1440-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | py3-gunicorn +9 | 22.0.0-r0 | — |
| Wolfi rolling | reflex | 0.4.9-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | gunicorn | < 22.0.0 | 22.0.0 | GHSA-w3h3-4rj7-4ph4 |
Advisories 16
- WID-SEC-2024-1328 Red Hat Ansible Automation Platform: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 18, 2026
- RHSA-2025:1335 Red Hat Security Advisory: RHUI 4.11 security, bugfix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2024:3781 Red Hat Security Advisory: Red Hat Ansible Automation Platform 2.4 Product Security and Bug Fix Update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2024:7987 Red Hat Security Advisory: Satellite 6.15.4 Security Update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2024:4054 Red Hat Security Advisory: Red Hat OpenStack Platform 16.2 (python-gunicorn) security update Red Hat Security Advisories (RHSA) · Aug 13, 2026
- RHSA-2024:2727 Red Hat Security Advisory: Red Hat OpenStack Platform 17.1 (python-gunicorn) security update Red Hat Security Advisories (RHSA) · Aug 13, 2026
- WID-SEC-2025-1559 Oracle Communications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- WID-SEC-2025-0823 Oracle Communications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- WID-SEC-2024-1228 Red Hat OpenStack: Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 15, 2026
- DLA-3851-1 gunicorn - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3996-1 gunicorn - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2024:1440-1 Security update for python-gunicorn SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:2881-1 Security update for python-gunicorn SUSE / openSUSE Security Updates · Feb 4, 2026
- NCSC-2025-0124 Kwetsbaarheden verholpen in Oracle Communications NCSC-NL (Netherlands) · Apr 16, 2025
- NCSC-2025-0028 Kwetsbaarheden verholpen in Oracle Analytics NCSC-NL (Netherlands) · Jan 22, 2025
- WID-SEC-2024-1427 IBM Business Automation Workflow: Schwachstelle ermöglicht Manipulation von Dateien BSI CERT-Bund (WID) · Jun 20, 2024