Red Hat Security Advisory: python3.12-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
The Red Hat Security Advisory RHSA-2026:1957 addresses three vulnerabilities in the python3.12-urllib3 package: 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; and CVE-2026-21441 describes a decompression-bomb safeguard bypass in the Streaming API when following HTTP redirects. These vulnerabilities affect Red Hat Enterprise Linux 9.4 Extended Update Support versions prior to 9.4.2. The advisory provides updated packages to mitigate these issues.
Potential Impact
These vulnerabilities can lead to resource exhaustion due to unbounded decompression chains and improper handling of compressed data, potentially impacting availability of applications using urllib3. The decompression-bomb safeguard bypass may allow attackers to circumvent protections designed to prevent denial-of-service conditions caused by maliciously crafted compressed data. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released updated python3.12-urllib3 packages (version 1.26.18-2.el9_4.2) that address these vulnerabilities. Users of affected Red Hat Enterprise Linux 9.4 Extended Update Support systems should apply the security update as detailed in the Red Hat advisory RHSA-2026:1957 and the referenced article https://access.redhat.com/articles/11258. Applying this update mitigates the described vulnerabilities.
Red Hat Security Advisory: python3.12-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
The Red Hat Security Advisory RHSA-2026:1957 addresses three vulnerabilities in the python3.12-urllib3 package: 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; and CVE-2026-21441 describes a decompression-bomb safeguard bypass in the Streaming API when following HTTP redirects. These vulnerabilities affect Red Hat Enterprise Linux 9.4 Extended Update Support versions prior to 9.4.2. The advisory provides updated packages to mitigate these issues.
Potential Impact
These vulnerabilities can lead to resource exhaustion due to unbounded decompression chains and improper handling of compressed data, potentially impacting availability of applications using urllib3. The decompression-bomb safeguard bypass may allow attackers to circumvent protections designed to prevent denial-of-service conditions caused by maliciously crafted compressed data. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released updated python3.12-urllib3 packages (version 1.26.18-2.el9_4.2) that address these vulnerabilities. Users of affected Red Hat Enterprise Linux 9.4 Extended Update Support systems should apply the security update as detailed in the Red Hat advisory RHSA-2026:1957 and the referenced article https://access.redhat.com/articles/11258. Applying this update mitigates the described vulnerabilities.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:1957
- Cve Count
- 3
- Additional Cves
- ["CVE-2025-66471","CVE-2026-21441"]
Threat ID: 6a16096be29bf47b50631958
Added to database: 05/26/2026, 20:58:19 UTC
Last enriched: 08/17/2026, 17:46:37 UTC
Last updated: 09/10/2026, 19:36:51 UTC
Views: 70
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