RHSA-2026:5853 - Security Advisory

Topic

An update for osbuild-composer is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions, and Red Hat Enterprise Linux 8.6 Telecommunications Update Service.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

A service for building customized OS artifacts, such as VM images and OSTree commits, that uses osbuild under the hood. Besides building images for local usage, it can also upload images directly to cloud. It is compatible with composer-cli and cockpit-composer clients.

Security Fix(es):

• crypto/x509: golang: Denial of Service due to excessive resource consumption via crafted certificate (CVE-2025-61729)
• golang: net/url: Memory exhaustion in query parameter parsing in net/url (CVE-2025-61726)

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.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support Extension 8.6 x86_64
• Red Hat Enterprise Linux Server - AUS 8.6 x86_64
• Red Hat Enterprise Linux Server - TUS 8.6 x86_64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 8.6 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 8.6 x86_64

Fixes

• BZ - 2418462 - CVE-2025-61729 crypto/x509: golang: Denial of Service due to excessive resource consumption via crafted certificate
• BZ - 2434432 - CVE-2025-61726 golang: net/url: Memory exhaustion in query parameter parsing in net/url

CVEs

• CVE-2025-61726
• CVE-2025-61729

References

• https://access.redhat.com/security/updates/classification/#important