Red Hat Security Advisory: python3.11-urllib3 security update
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.
AI Analysis
Technical Summary
This advisory addresses three security issues in the urllib3 library used by python3.11 on Red Hat Enterprise Linux 8. CVE-2025-66418 involves an unbounded decompression chain that can cause resource exhaustion. CVE-2025-66471 concerns improper handling of highly compressed data by the urllib3 streaming API. CVE-2026-21441 describes a vulnerability where the decompression-bomb safeguard can be bypassed when following HTTP redirects in the streaming API. These issues could lead to denial of service or resource exhaustion conditions. Red Hat has released updated python3.11-urllib3 packages to fix these vulnerabilities.
Potential Impact
The vulnerabilities can lead to resource exhaustion or denial of service conditions when processing specially crafted compressed data streams using urllib3's streaming API. This can affect systems running vulnerable versions of python3.11-urllib3 on Red Hat Enterprise Linux 8, potentially impacting availability of affected services.
Mitigation Recommendations
Red Hat has released updated python3.11-urllib3 packages that address these vulnerabilities. Users should apply the security update for python3.11-urllib3 as provided in Red Hat Enterprise Linux 8 and Extended Life Cycle 8.10. Details and instructions for applying the update are available at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated beyond applying the official update.
Red Hat Security Advisory: python3.11-urllib3 security update
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.
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This advisory addresses three security issues in the urllib3 library used by python3.11 on Red Hat Enterprise Linux 8. CVE-2025-66418 involves an unbounded decompression chain that can cause resource exhaustion. CVE-2025-66471 concerns improper handling of highly compressed data by the urllib3 streaming API. CVE-2026-21441 describes a vulnerability where the decompression-bomb safeguard can be bypassed when following HTTP redirects in the streaming API. These issues could lead to denial of service or resource exhaustion conditions. Red Hat has released updated python3.11-urllib3 packages to fix these vulnerabilities.
Potential Impact
The vulnerabilities can lead to resource exhaustion or denial of service conditions when processing specially crafted compressed data streams using urllib3's streaming API. This can affect systems running vulnerable versions of python3.11-urllib3 on Red Hat Enterprise Linux 8, potentially impacting availability of affected services.
Mitigation Recommendations
Red Hat has released updated python3.11-urllib3 packages that address these vulnerabilities. Users should apply the security update for python3.11-urllib3 as provided in Red Hat Enterprise Linux 8 and Extended Life Cycle 8.10. Details and instructions for applying the update are available at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated beyond applying the official update.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:1224
- Cve Count
- 3
- Additional Cves
- ["CVE-2025-66471","CVE-2026-21441"]
Threat ID: 6a16096de29bf47b50634103
Added to database: 05/26/2026, 20:58:21 UTC
Last enriched: 08/10/2026, 17:58:28 UTC
Last updated: 09/10/2026, 19:36:51 UTC
Views: 80
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.