RHSA-2026:59562: Important: osbuild-composer security update

Published Aug 25, 2026
·
Updated

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): golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing (CVE-2026-39821) golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via HTML parsing bypass (CVE-2026-27136) golang.org/x/net/html: golang.org/x/net/html: Arbitrary code execution via Cross-Site Scripting (CVE-2026-25681) golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via unexpected HTML tree rendering (CVE-2026-42502) 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.

Other sources

Important: osbuild-composer security update

— Red Hat

Affected Software

41 affected componentsFixes available
Red Hat Red Hat Enterprise Linux for x86_64 - Extended Life Cycle
Red Hat Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle
Red Hat Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle
Red Hat Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle
Red Hat Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
Red Hat Red Hat Enterprise Linux for ARM 64 - 4 years of updates
Red Hat Red Hat Enterprise Linux Server - AUS
Red Hat Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions
Red Hat Red Hat Enterprise Linux for IBM z Systems - 4 years of updates
redhat/osbuild-composer<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-core<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-core-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-debugsource<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-tests-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-worker<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-worker-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-core<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-core-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-debugsource<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-tests-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-worker<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-worker-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-core<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-core-debuginfo<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-debuginfo<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-debugsource<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-tests-debuginfo<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-worker<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-worker-debuginfo<101.3-4.el9_4.5.aa
101.3-4.el9_4.5.aa
redhat/osbuild-composer-core<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-core-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-debugsource<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-tests-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-worker<101.3-4.el9_4.5
101.3-4.el9_4.5
redhat/osbuild-composer-worker-debuginfo<101.3-4.el9_4.5
101.3-4.el9_4.5

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/osbuild-composer to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  2. Upgrade

    Upgrade redhat/osbuild-composer-core to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  3. Upgrade

    Upgrade redhat/osbuild-composer-core-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  4. Upgrade

    Upgrade redhat/osbuild-composer-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  5. Upgrade

    Upgrade redhat/osbuild-composer-debugsource to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  6. Upgrade

    Upgrade redhat/osbuild-composer-tests-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  7. Upgrade

    Upgrade redhat/osbuild-composer-worker to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  8. Upgrade

    Upgrade redhat/osbuild-composer-worker-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5
  9. Upgrade

    Upgrade redhat/osbuild-composer to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  10. Upgrade

    Upgrade redhat/osbuild-composer-core to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  11. Upgrade

    Upgrade redhat/osbuild-composer-core-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  12. Upgrade

    Upgrade redhat/osbuild-composer-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  13. Upgrade

    Upgrade redhat/osbuild-composer-debugsource to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  14. Upgrade

    Upgrade redhat/osbuild-composer-tests-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  15. Upgrade

    Upgrade redhat/osbuild-composer-worker to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  16. Upgrade

    Upgrade redhat/osbuild-composer-worker-debuginfo to a version that resolves this vulnerability.

    Fixed in 101.3-4.el9_4.5.aa
  17. Upgrade

    Upgrade osbuild-composer to a version that resolves this vulnerability.

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

Event History

Aug 25, 2026
Advisory Published
via Red Hat·12:00 AM
Data Sourced
via Red Hat·12:00 AM
RemedyDescriptionAffected Software
Advisory Published
via Red Hat·07:03 PM
Data Sourced
via Red Hat·07:03 PM
Severity

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203