RHSA-2026:57541: Important: osbuild-composer security update

Published Aug 20, 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) github.com/labstack/echo: Echo: Unauthorized Information Disclosure via URL Path Decoding Discrepancy (CVE-2026-55677) 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

45 affected componentsFixes available
Red Hat Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Red Hat Enterprise Linux Server - AUS
Red Hat Red Hat Enterprise Linux for x86_64 - Extended Update Support
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
Red Hat Red Hat Enterprise Linux for x86_64 - Extended Life Cycle
Red Hat Red Hat Enterprise Linux for ARM 64 - 4 years of updates
Red Hat Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle
Red Hat Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle
Red Hat Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
Red Hat Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle
redhat/osbuild-composer<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-core<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-core-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-debugsource<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-tests-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-worker<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-worker-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-core<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-core-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-debugsource<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-tests-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-worker<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-worker-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-core<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-core-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-debugsource<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-tests-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-worker<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer-worker-debuginfo<132.2-10.el9_6
132.2-10.el9_6
redhat/osbuild-composer<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-core<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-core-debuginfo<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-debuginfo<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-debugsource<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-tests-debuginfo<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-worker<132.2-10.el9_6.aa
132.2-10.el9_6.aa
redhat/osbuild-composer-worker-debuginfo<132.2-10.el9_6.aa
132.2-10.el9_6.aa

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 132.2-10.el9_6
  2. Upgrade

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

    Fixed in 132.2-10.el9_6
  3. Upgrade

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

    Fixed in 132.2-10.el9_6
  4. Upgrade

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

    Fixed in 132.2-10.el9_6
  5. Upgrade

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

    Fixed in 132.2-10.el9_6
  6. Upgrade

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

    Fixed in 132.2-10.el9_6
  7. Upgrade

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

    Fixed in 132.2-10.el9_6
  8. Upgrade

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

    Fixed in 132.2-10.el9_6
  9. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  10. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  11. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  12. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  13. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  14. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  15. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  16. Upgrade

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

    Fixed in 132.2-10.el9_6.aa
  17. Upgrade

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

    Patch osbuild-composer security update
  18. Upgrade

    Upgrade golang.org/x/net/idna to a version that resolves this vulnerability.

    Patch CVE-2026-39821

Event History

Aug 20, 2026
Advisory Published
via Red Hat·12:00 AM
Data Sourced
via Red Hat·12:00 AM
RemedyDescriptionAffected Software
Advisory Published
via Red Hat·01:28 PM
Data Sourced
via Red Hat·01:28 PM
Severity

Frequently Asked Questions

1

Which components are covered by this update?

The update covers osbuild-composer and osbuild-composer-core, along with the osbuild-composer-worker package and the listed debuginfo, debugsource, and test debuginfo packages.

2

What security issues are addressed?

The update addresses CVE-2026-39821, a privilege-escalation issue in golang.org/x/net/idna related to incorrect Punycode label processing, and CVE-2026-55677, an unauthorized information-disclosure issue in github.com/labstack/echo caused by URL path decoding discrepancies.

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