AlmaLinux 2499 Published by

The AlmaLinux Security team has issued several security updates for the python3-urllib3 package, which includes fixes for three vulnerabilities: unbounded decompression chain leading to resource exhaustion (CVE-2025-66418), improper handling of highly compressed data (CVE-2025-66471), and bypassing of decompression-bomb safeguard when following HTTP redirects (CVE-2026-21441). These updates are important and affect multiple versions of the python3-urllib3 package, including those for AlmaLinux 8 and 9.

ALSA-2026:1226: python3.12-urllib3 security update (Important)
ALSA-2026:1224: python3.11-urllib3 security update (Important)
ALSA-2026:1087: python-urllib3 security update (Important)
ALSA-2026:1089: python3.11-urllib3 security update (Important)
ALSA-2026:1088: python3.12-urllib3 security update (Important)




ALSA-2026:1226: python3.12-urllib3 security update (Important)


Hi,

You are receiving an AlmaLinux Security update email because you subscribed to receive errata notifications from AlmaLinux.

AlmaLinux: 8
Type: Security
Severity: Important
Release date: 2026-01-27

Summary:

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.

Full details, updated packages, references, and other related information: https://errata.almalinux.org/8/ALSA-2026-1226.html

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Kind regards,
AlmaLinux Team



ALSA-2026:1224: python3.11-urllib3 security update (Important)


Hi,

You are receiving an AlmaLinux Security update email because you subscribed to receive errata notifications from AlmaLinux.

AlmaLinux: 8
Type: Security
Severity: Important
Release date: 2026-01-27

Summary:

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.

Full details, updated packages, references, and other related information: https://errata.almalinux.org/8/ALSA-2026-1224.html

This message is automatically generated, please don’t reply. For further questions, please, contact us via the AlmaLinux community chat: https://chat.almalinux.org/.
Want to change your notification settings? Sign in and manage mailing lists on https://lists.almalinux.org.

Kind regards,
AlmaLinux Team



ALSA-2026:1087: python-urllib3 security update (Important)


Hi,

You are receiving an AlmaLinux Security update email because you subscribed to receive errata notifications from AlmaLinux.

AlmaLinux: 9
Type: Security
Severity: Important
Release date: 2026-01-27

Summary:

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.

Full details, updated packages, references, and other related information: https://errata.almalinux.org/9/ALSA-2026-1087.html

This message is automatically generated, please don’t reply. For further questions, please, contact us via the AlmaLinux community chat: https://chat.almalinux.org/.
Want to change your notification settings? Sign in and manage mailing lists on https://lists.almalinux.org.

Kind regards,
AlmaLinux Team



ALSA-2026:1089: python3.11-urllib3 security update (Important)


Hi,

You are receiving an AlmaLinux Security update email because you subscribed to receive errata notifications from AlmaLinux.

AlmaLinux: 9
Type: Security
Severity: Important
Release date: 2026-01-27

Summary:

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.

Full details, updated packages, references, and other related information: https://errata.almalinux.org/9/ALSA-2026-1089.html

This message is automatically generated, please don’t reply. For further questions, please, contact us via the AlmaLinux community chat: https://chat.almalinux.org/.
Want to change your notification settings? Sign in and manage mailing lists on https://lists.almalinux.org.

Kind regards,
AlmaLinux Team



ALSA-2026:1088: python3.12-urllib3 security update (Important)


Hi,

You are receiving an AlmaLinux Security update email because you subscribed to receive errata notifications from AlmaLinux.

AlmaLinux: 9
Type: Security
Severity: Important
Release date: 2026-01-27

Summary:

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.

Full details, updated packages, references, and other related information: https://errata.almalinux.org/9/ALSA-2026-1088.html

This message is automatically generated, please don’t reply. For further questions, please, contact us via the AlmaLinux community chat: https://chat.almalinux.org/.
Want to change your notification settings? Sign in and manage mailing lists on https://lists.almalinux.org.

Kind regards,
AlmaLinux Team