Issued:

2026-02-16

Updated:

2026-02-16

RHSA-2026:2717 - Important: python-urllib3 security update

Synopsis

Important: python-urllib3 security update

Type/Severity

Security Advisory Important

Topic

An update for python-urllib3 is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions, and Red Hat Enterprise Linux 8.6 Telecommunications Update Service.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• urllib3: urllib3: Unbounded decompression chain leads to resource exhaustion (CVE-2025-66418)

• urllib3: urllib3 Streaming API improperly handles highly compressed data (CVE-2025-66471)

• urllib3: urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API) (CVE-2026-21441)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

Updated Packages

• python-urllib3-1.24.2-5.el8_6.4.src.rpm
• python3-urllib3-1.24.2-5.el8_6.4.noarch.rpm

Fixes

• This content is not included.BZ - 2419455
• This content is not included.BZ - 2419467
• This content is not included.BZ - 2427726

CVEs

• CVE-2025-66418
• CVE-2025-66471
• CVE-2026-21441

References

• https://access.redhat.com/security/updates/classification/#important

Additional information

• The Red Hat security contact is This content is not included.secalert@redhat.com. More contact details at https://access.redhat.com/security/team/contact/.
• Offline Security Data data is available for integration with other systems. See Offline Security Data API to get started.