Description
urllib3 is an HTTP client library for Python. From 1.26.0 until 2.8.0, the proxy_ssl_context, proxy_assert_hostname, proxy_assert_fingerprint, ssl_context, cert_reqs, verify_mode, use_forwarding_for_https=True, and CERT_NONE configuration paths fail to remain separated because target-server TLS settings are incorrectly applied to the HTTPS proxy connection. The trigger is that an application uses an HTTPS proxy and configures target-server TLS settings that must remain separate from the proxy TLS handshake, including HTTPS forwarding with target-specific identity or credentials. Applying cert_reqs=CERT_NONE can overwrite proxy_ssl_context.verify_mode in place, and the mutation persists so later connections reusing the same context may connect to the HTTPS proxy without certificate verification. The attack mechanism is that an attacker intercepts and impersonates the HTTPS proxy after the effective proxy policy accepts the attacker's certificate. The impact is that the attacker can observe or modify forwarded traffic or receive a target TLS client certificate, while CONNECT tunneling still preserves the separate end-to-end target TLS connection. This issue is fixed in version 2.8.0.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| urllib3 | urllib3 | >= 1.26.0, < 2.8.0 | — |
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 | python-urllib3 | 2.8.0-1 | — |
| Debian 13 | python-urllib3 | No fix yet | — |
| Debian 12 | python-urllib3 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | python-pip | No fix yet | — |
| Ubuntu 26.04 LTS | python-urllib3 | 2.6.3-1ubuntu1.2 | USN-8926-1 |
| Ubuntu 24.04 LTS | python-urllib3 | 2.0.7-1ubuntu0.8 | USN-8926-1 |
| Ubuntu 22.04 LTS | python-urllib3 | 1.26.5-1~exp1ubuntu0.8 | USN-8926-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | python-pip | No fix yet | — |
| Ubuntu Pro 24.04 LTS | python-pip | No fix yet | — |
| Ubuntu Pro 22.04 LTS | python-pip | No fix yet | — |
| Ubuntu Pro 20.04 LTS | python-pip | No fix yet | — |
| Ubuntu Pro 20.04 LTS | python-urllib3 | 1.25.8-2ubuntu0.4+esm6 | USN-8926-1 |
| Ubuntu Pro 18.04 LTS | python-pip | No fix yet | — |
| Ubuntu Pro 18.04 LTS | python-urllib3 | 1.22-1ubuntu0.18.04.2+esm5 | USN-8926-1 |
| Ubuntu Pro 16.04 LTS | python-pip | No fix yet | — |
| Ubuntu Pro 14.04 LTS | python-pip | No fix yet | — |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | python3-urllib3 | 1.26.19-4.el10_2.2 | ALSA-2026:85930 |
| AlmaLinux 10 | python3.14-urllib3 | 2.6.3-2.el10_2.6 | ALSA-2026:84578 |
| AlmaLinux 9 | python3-urllib3 | 1.26.5-8.el9_8.2 | ALSA-2026:90494 |
| AlmaLinux 9 | python3.12-urllib3 | 1.26.19-3.el9_8.2 | ALSA-2026:85929 |
| AlmaLinux 9 | python3.14-urllib3 | 2.6.3-2.el9_8.6 | ALSA-2026:84577 |
| AlmaLinux 8 | python3.12-urllib3 | 1.26.19-5.el8_10 | ALSA-2026:92474 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | python-urllib3 | 1.26.19-4.el10_2.2 | RLSA-2026:85930 |
| Rocky Linux 10 | python3.14-urllib3 | 2.6.3-2.el10_2.6 | RLSA-2026:84578 |
| Rocky Linux 9 | python-urllib3 | 1.26.5-8.el9_8.2 | RLSA-2026:90494 |
| Rocky Linux 9 | python3.12-urllib3 | 1.26.19-3.el9_8.2 | RLSA-2026:85929 |
| Rocky Linux 9 | python3.14-urllib3 | 2.6.3-2.el9_8.6 | RLSA-2026:84577 |
| Rocky Linux 8 | python3.12-urllib3 | 1.26.19-5.el8_10 | RLSA-2026:92474 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES 15 SP6 | python-urllib3_1 | 1.26.18-150600.3.14.1 | SUSE-SU-2026:4948-1 |
| SLES 15 SP5 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES 15 SP4 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES 3 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES 3 | python-urllib3_1 | 1.26.18-150600.3.14.1 | SUSE-SU-2026:4948-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | python-urllib3 | 2.5.0-160000.8.1 | SUSE-SU-2026:24217-1 |
| SLES for SAP 16.0 | python-urllib3_1 | 1.26.20-160000.5.1 | SUSE-SU-2026:24660-1 |
| SLES for SAP 15 SP6 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES for SAP 15 SP6 | python-urllib3_1 | 1.26.18-150600.3.14.1 | SUSE-SU-2026:4948-1 |
| SLES for SAP 15 SP5 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES for SAP 15 SP4 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLES 16.0 | python-urllib3 | 2.5.0-160000.8.1 | SUSE-SU-2026:24217-1 |
| SLES 16.0 | python-urllib3_1 | 1.26.20-160000.5.1 | SUSE-SU-2026:24660-1 |
| SLE Micro 6.2 | python-urllib3 | 2.5.0-160000.8.1 | SUSE-SU-2026:24125-1 |
| SLE HPC 15 SP5 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
| SLE HPC 15 SP4 | python-urllib3 | 2.0.7-150400.7.36.1 | SUSE-SU-2026:4704-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-urllib3 | 2.8.0-1.1 | openSUSE-SU-2026:12044-1 |
| openSUSE Tumbleweed | python-urllib3_1 | 1.26.20-8.1 | openSUSE-SU-2026:12119-1 |
| openSUSE Leap 16.0 | python-urllib3 | 2.5.0-160000.8.1 | openSUSE-SU-2026:22071-1 |
| openSUSE Leap 16.0 | python-urllib3_1 | 1.26.20-160000.5.1 | openSUSE-SU-2026:22252-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python3 +4 | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | python3-urllib3 | 1.26.19-4.el10_2.2 | ELSA-2026-85930 |
| Oracle Linux 10 | python3.14-urllib3 | 2.6.3-2.el10_2.6 | ELSA-2026-84578 |
| Oracle Linux 9 | python3-urllib3 | 1.26.5-8.el9_8.2 | ELSA-2026-90494 |
| Oracle Linux 9 | python3.12-urllib3 | 1.26.19-3.el9_8.2 | ELSA-2026-85929 |
| Oracle Linux 9 | python3.14-urllib3 | 2.6.3-2.el9_8.6 | ELSA-2026-84577 |
| Oracle Linux 8 | python3.12-urllib3 | 1.26.19-5.el8_10 | ELSA-2026-92474 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | confluent-docker-utils | 0.0.172-r4 | — |
| Wolfi rolling | datadog-agent-7.77-core-integrations | 7.77.3-r27 | — |
| Wolfi rolling | datadog-agent-7.78 | 7.78.4-r23 | — |
| Wolfi rolling | datadog-agent-7.79 +5 | No fix yet | — |
| Wolfi rolling | datadog-agent-7.81 | 7.81.3-r10 | — |
| Wolfi rolling | jwt-tool | 2.3.0-r7 | — |
| Wolfi rolling | kserve-storage-controller | 0.21.0-r2 | — |
| Wolfi rolling | kubeflow-pipelines-apiserver | 2.17.2-r8 | — |
| Wolfi rolling | kubeflow-pipelines-visualization-server | 2.17.2-r4 | — |
| Wolfi rolling | open-webui | 0.11.4-r3 | — |
| Wolfi rolling | py3-cassandra-medusa | 0.30.1-r2 | — |
| Wolfi rolling | py3.10-pip-base +4 | 26.2.1-r2 | — |
| Wolfi rolling | py3.10-pipenv +3 | 2026.8.0-r2 | — |
| Wolfi rolling | pypy-3.10 | 7.3.19-r21 | — |
| Wolfi rolling | superset-6.0 | 6.0.0-r18 | — |
| Wolfi rolling | superset-6.1 | 6.1.0-r11 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | urllib3 | >= 1.26.0, < 2.8.0 | 2.8.0 | GHSA-8988-9cw3-xx77 |
Advisories 30
- WID-SEC-2026-4111 Red Hat Ansible Automation Platform: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- WID-SEC-2026-4024 Red Hat Quay und Enterprise Linux (pypdf, urllib3, URI): Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- SUSE-SU-2026:24660-1 Security update for python-urllib3_1 SUSE / openSUSE Security Updates · Nov 12, 2026
- openSUSE-SU-2026:22252-1 Security update for python-urllib3_1 SUSE / openSUSE Security Updates · Nov 11, 2026
- RLSA-2026:85930 Important: python-urllib3 security update Rocky Linux Security Advisories · Nov 3, 2026
- SUSE-SU-2026:4948-1 Security update for python-urllib3_1 SUSE / openSUSE Security Updates · Nov 2, 2026
- RLSA-2026:92474 Important: python3.12-urllib3 security update Rocky Linux Security Advisories · Oct 30, 2026
- ALSA-2026:92474 Important: python3.12-urllib3 security update AlmaLinux Security Advisories · Oct 29, 2026
- RLSA-2026:90494 Important: python-urllib3 security update Rocky Linux Security Advisories · Oct 29, 2026
- ALSA-2026:84577 Important: python3.14-urllib3 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:85929 Important: python3.12-urllib3 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:90494 Important: python-urllib3 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:84578 Important: python3.14-urllib3 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:85930 Important: python-urllib3 security update AlmaLinux Security Advisories · Oct 29, 2026
- ELSA-2026-92474 Important: python3.12-urllib3 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Oct 29, 2026
- ELSA-2026-90494 Important: python-urllib3 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Oct 26, 2026
- RLSA-2026:85929 Important: python3.12-urllib3 security update Rocky Linux Security Advisories · Oct 22, 2026
- SUSE-SU-2026:24217-1 Security update for python-urllib3 SUSE / openSUSE Security Updates · Oct 21, 2026
- RLSA-2026:84577 Important: python3.14-urllib3 security update Rocky Linux Security Advisories · Oct 20, 2026
- RLSA-2026:84578 Important: python3.14-urllib3 security update Rocky Linux Security Advisories · Oct 20, 2026
- ELSA-2026-85930 Important: python-urllib3 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Oct 20, 2026
- ELSA-2026-85929 Important: python3.12-urllib3 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Oct 20, 2026
- openSUSE-SU-2026:22071-1 Security update for python-urllib3 SUSE / openSUSE Security Updates · Oct 19, 2026
- ELSA-2026-84578 Important: python3.14-urllib3 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Oct 19, 2026
- ELSA-2026-84577 Important: python3.14-urllib3 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Oct 19, 2026
- USN-8926-1 python-urllib3 vulnerabilities Ubuntu Security Notices (USN) · Oct 17, 2026
- SUSE-SU-2026:4704-1 Security update for python-urllib3 SUSE / openSUSE Security Updates · Oct 17, 2026
- openSUSE-SU-2026:12119-1 python313-urllib3_1-1.26.20-8.1 on GA media SUSE / openSUSE Security Updates · Oct 14, 2026
- SUSE-SU-2026:24125-1 Security update for python-urllib3 SUSE / openSUSE Security Updates · Oct 13, 2026
- openSUSE-SU-2026:12044-1 python313-urllib3-2.8.0-1.1 on GA media SUSE / openSUSE Security Updates · Oct 5, 2026
References
- https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77
- https://github.com/urllib3/urllib3/pull/5093
- https://github.com/urllib3/urllib3/commit/07408cec79d1856d81bb42c74a904a24fdb9e465
- https://github.com/urllib3/urllib3/commit/b6447295fff7b38fdffc67e0df9712d60cef3cc3
- https://github.com/urllib3/urllib3/releases/tag/2.8.0