RHSA-2026:3753 - Security Advisory

Topic

An update for osbuild-composer is now available for Red Hat Enterprise Linux 9.

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: archive/zip: Excessive CPU consumption when building archive index in archive/zip (CVE-2025-61728)
• golang: net/url: Memory exhaustion in query parameter parsing in net/url (CVE-2025-61726)
• crypto/tls: Unexpected session resumption in crypto/tls (CVE-2025-68121)

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 9 x86_64
• Red Hat Enterprise Linux for IBM z Systems 9 s390x
• Red Hat Enterprise Linux for Power, little endian 9 ppc64le
• Red Hat Enterprise Linux for ARM 64 9 aarch64

Fixes

• BZ - 2418462 - CVE-2025-61729 crypto/x509: golang: Denial of Service due to excessive resource consumption via crafted certificate
• BZ - 2434431 - CVE-2025-61728 golang: archive/zip: Excessive CPU consumption when building archive index in archive/zip
• BZ - 2434432 - CVE-2025-61726 golang: net/url: Memory exhaustion in query parameter parsing in net/url
• BZ - 2437111 - CVE-2025-68121 crypto/tls: Unexpected session resumption in crypto/tls

CVEs

• CVE-2025-61726
• CVE-2025-61728
• CVE-2025-61729
• CVE-2025-68121

References

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