Red Hat Security Advisory: python-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 covers three security vulnerabilities in the python-urllib3 library: CVE-2025-66418, an unbounded decompression chain that can cause resource exhaustion; CVE-2025-66471, improper handling of highly compressed data in the streaming API; and CVE-2026-21441, a decompression-bomb safeguard bypass when following HTTP redirects in the streaming API. These vulnerabilities affect Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions and related architectures. Red Hat has issued a security update (python-urllib3-1.26.5-3.el9_0.2) that addresses these issues. The advisory rates the impact as Important (high severity) but does not provide CVSS scores. No known exploits in the wild have been reported.
Potential Impact
The vulnerabilities can lead to resource exhaustion and bypass of decompression safeguards in the urllib3 library, potentially impacting applications that process compressed HTTP content using the streaming API. This could degrade service availability or cause denial-of-service conditions. No active exploitation has been reported. The impact is rated as high by Red Hat.
Mitigation Recommendations
A security update is available from Red Hat that addresses these vulnerabilities in python-urllib3 version 1.26.5-3.el9_0.2. Users should apply this update promptly to mitigate the issues. Refer to Red Hat advisory RHSA-2026:1618 and the article https://access.redhat.com/articles/11258 for detailed update instructions. No additional mitigations are specified.
Red Hat Security Advisory: python-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
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This advisory covers three security vulnerabilities in the python-urllib3 library: CVE-2025-66418, an unbounded decompression chain that can cause resource exhaustion; CVE-2025-66471, improper handling of highly compressed data in the streaming API; and CVE-2026-21441, a decompression-bomb safeguard bypass when following HTTP redirects in the streaming API. These vulnerabilities affect Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions and related architectures. Red Hat has issued a security update (python-urllib3-1.26.5-3.el9_0.2) that addresses these issues. The advisory rates the impact as Important (high severity) but does not provide CVSS scores. No known exploits in the wild have been reported.
Potential Impact
The vulnerabilities can lead to resource exhaustion and bypass of decompression safeguards in the urllib3 library, potentially impacting applications that process compressed HTTP content using the streaming API. This could degrade service availability or cause denial-of-service conditions. No active exploitation has been reported. The impact is rated as high by Red Hat.
Mitigation Recommendations
A security update is available from Red Hat that addresses these vulnerabilities in python-urllib3 version 1.26.5-3.el9_0.2. Users should apply this update promptly to mitigate the issues. Refer to Red Hat advisory RHSA-2026:1618 and the article https://access.redhat.com/articles/11258 for detailed update instructions. No additional mitigations are specified.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:1618
- Cve Count
- 3
- Additional Cves
- ["CVE-2025-66471","CVE-2026-21441"]
Threat ID: 6a16096ce29bf47b506334c0
Added to database: 05/26/2026, 20:58:20 UTC
Last enriched: 08/10/2026, 17:51:05 UTC
Last updated: 09/10/2026, 19:36:51 UTC
Views: 114
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