AlmaLinux rolled out a series of critical security patches that affect both version nine and ten of its platform. The updates address multiple high risk vulnerabilities across .NET versions eight and nine, FreeRDP, Thunderbird, and libarchive. Attackers could potentially exploit these flaws to run malicious code remotely or crash systems through memory handling errors and parsing bugs. Administrators need to deploy these fixes right away since the issues carry an important severity rating and leave systems wide open to exploitation.

ALSA-2026:8472: .NET 9.0 security update (Important)
ALSA-2026:8492: libarchive security update (Important)
ALSA-2026:8457: freerdp security update (Important)
ALSA-2026:8469: .NET 8.0 security update (Important)
ALSA-2026:8459: thunderbird security update (Important)
ALSA-2026:8510: libarchive security update (Important)

ALSA-2026:8472: .NET 9.0 security update (Important)

Hi,

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

AlmaLinux: 10
Type: Security
Severity: Important
Release date: 2026-04-17

Summary:

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 9.0.116 and .NET Runtime 9.0.15.Security Fix(es):

* dotnet: .NET: Security Bypass and Denial of Service Vulnerability (CVE-2026-26171)
* dotnet: .NET: Denial of Service via stack overflow (CVE-2026-32203)
* dotnet: .NET: Denial of Service via Infinite Recursion in XmlDecryptionTransform (CVE-2026-33116)
* dotnet: Dotnet: SMTP Command Injection and Header Injection via MailAddress parsing flaw (CVE-2026-32178)

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/10/ALSA-2026-8472.html

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Kind regards,
AlmaLinux Team

ALSA-2026:8492: libarchive security update (Important)

Hi,

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

AlmaLinux: 10
Type: Security
Severity: Important
Release date: 2026-04-17

Summary:

The libarchive programming library can create and read several different streaming archive formats, including GNU tar, cpio, and ISO 9660 CD-ROM images. Libarchive is used notably in the bsdtar utility, scripting language bindings such as python-libarchive, and several popular desktop file managers.

Security Fix(es):

* libarchive: libarchive: Information disclosure via heap out-of-bounds read in RAR archive processing (CVE-2026-4424)

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/10/ALSA-2026-8492.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/.
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Kind regards,
AlmaLinux Team

ALSA-2026:8457: freerdp 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: 2026-04-17

Summary:

FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. The xfreerdp client can connect to RDP servers such as Microsoft Windows machines, xrdp, and VirtualBox.

Security Fix(es):

* FreeRDP: FreeRDP: Heap buffer overflow allows arbitrary code execution via crafted pixel data (CVE-2026-33984)
* FreeRDP: FreeRDP: Denial of Service via specially crafted Remote Desktop Protocol messages (CVE-2026-33983)

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-2026-8457.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/.
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Kind regards,
AlmaLinux Team

ALSA-2026:8469: .NET 8.0 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: 2026-04-17

Summary:

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 8.0.126 and .NET Runtime 8.0.26.Security Fix(es):

* dotnet: .NET: Security Bypass and Denial of Service Vulnerability (CVE-2026-26171)
* dotnet: .NET: Denial of Service via stack overflow (CVE-2026-32203)
* dotnet: .NET: Denial of Service via Infinite Recursion in XmlDecryptionTransform (CVE-2026-33116)
* dotnet: Dotnet: SMTP Command Injection and Header Injection via MailAddress parsing flaw (CVE-2026-32178)

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-2026-8469.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/.
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Kind regards,
AlmaLinux Team

ALSA-2026:8459: thunderbird 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: 2026-04-17

Summary:

Mozilla Thunderbird is a standalone mail and newsgroup client.

Security Fix(es):

* libpng: libpng: Arbitrary code execution due to use-after-free vulnerability (CVE-2026-33416)
* libpng: libpng: Information disclosure and denial of service via out-of-bounds read/write in Neon palette expansion (CVE-2026-33636)
* thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5734)
* thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5731)
* firefox: thunderbird: Incorrect boundary conditions, integer overflow in the Graphics: Text component (CVE-2026-5732)

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-2026-8459.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/.
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Kind regards,
AlmaLinux Team

ALSA-2026:8510: libarchive 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: 2026-04-17

Summary:

The libarchive programming library can create and read several different streaming archive formats, including GNU tar, cpio, and ISO 9660 CD-ROM images. Libarchive is used notably in the bsdtar utility, scripting language bindings such as python-libarchive, and several popular desktop file managers.

Security Fix(es):

* libarchive: libarchive: Information disclosure via heap out-of-bounds read in RAR archive processing (CVE-2026-4424)
* libarchive: libarchive: Arbitrary code execution via integer overflow in ISO9660 image processing (CVE-2026-5121)

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-2026-8510.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/.
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Kind regards,
AlmaLinux Team