A vulnerability (CVE-2025-66471, CVSS 7.5 HIGH) in the python-urllib3 Streaming API allows improper handling of highly compressed data, which could lead to resource exhaustion or denial-of-service attacks. The NVD data indicates that python-urllib3 versions from 1.0 up to, but not including, 2.6.0 are affected. The fixed version is 2.6.0, and administrators should apply the Red Hat-provided patches for the affected ELS systems.
Red Hat Product Errata RHSA-2026:11722 - Security Advisory Issued: 2026-04-29 Updated: 2026-04-29 RHSA-2026:11722 - Security Advisory Overview Updated Packages Synopsis Important: python-urllib3 security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for python-urllib3 is now available for Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION. 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 Streaming API improperly handles highly compressed data (CVE-2025-66471) 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 Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64 Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386 Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x Fixes BZ - 2419467 - CVE-2025-66471 urllib3: urllib3 Streaming API improperly handles highly compressed data CVEs CVE-2025-66471 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 SRPM python-urllib3-1.10.2-3.el6_10.1.src.rpm SHA-256: 40a21f0850397ef26c6551d501c1248f25f1746a82e7c0f2fa6d0a22748d108c x86_64 python-urllib3-1.10.2-3.el6_10.1.noarch.rpm SHA-256: d1e92e80157af6bdc067fab3cdbf5d6db623368efe0af3dc689515f260e43987 i386 python-urllib3-1.10.2-3.el6_10.1.noarch.rpm SHA-256: d1e92e80157af6bdc067fab3cdbf5d6db623368efe0af3dc689515f260e43987 Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 SRPM python-urllib3-1.10.2-3.el6_10.1.src.rpm SHA-256: 40a21f0850397ef26c6551d501c1248f25f1746a82e7c0f2fa6d0a22748d108c s390x python-urllib3-1.10.2-3.el6_10.1.noarch.rpm SHA-256: d1e92e80157af6bdc067fab3cdbf5d6db623368efe0af3dc689515f260e43987 The Red Hat security contact is secalert@redhat.com . More contact details at https://access.redhat.com/security/team/contact/ .