RHSA-2026:59560: Important: osbuild-composer security update

Q: Which components are covered by this update?

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

Q: What types of security issues are addressed?

The update fixes three issues in golang.org/x/net/html: HTML parsing-bypass cross-site scripting, arbitrary code execution through cross-site scripting, and cross-site scripting caused by unexpected HTML tree rendering.

Q: Does the advisory provide a temporary mitigation if the update cannot be installed immediately?

No temporary mitigation or configuration workaround is provided in the advisory data. The stated remediation is the 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/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

45 affected componentsFixes available

Red Hat Red Hat Enterprise Linux for Power, little endian - Extended Update Support

Red Hat Red Hat Enterprise Linux for IBM z Systems - 4 years of updates

Red Hat Red Hat Enterprise Linux for IBM z Systems - Extended Update Support

Red Hat Red Hat Enterprise Linux for Power, little endian - 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 - Extended Update Support

Red Hat Red Hat Enterprise Linux for x86_64 - Extended Update Support

Red Hat Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle

Red Hat Red Hat Enterprise Linux for x86_64 - Extended Life Cycle

Red Hat Red Hat Enterprise Linux for x86_64 - 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 IBM z Systems - Extended Life Cycle

redhat/osbuild-composer<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-core<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-core-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-debugsource<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-tests-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-worker<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-worker-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-core<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-core-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-debugsource<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-tests-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-worker<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-worker-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-core<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-core-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-debugsource<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-tests-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-worker<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer-worker-debuginfo<132.2-11.el9_6

132.2-11.el9_6

redhat/osbuild-composer<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-core<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-core-debuginfo<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-debuginfo<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-debugsource<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-tests-debuginfo<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-worker<132.2-11.el9_6.aa

132.2-11.el9_6.aa

redhat/osbuild-composer-worker-debuginfo<132.2-11.el9_6.aa

132.2-11.el9_6.aa

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade redhat/osbuild-composer to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-core to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-core-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-debugsource to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-tests-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-worker to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer-worker-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6
Upgrade
Upgrade redhat/osbuild-composer to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-core to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-core-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-debugsource to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-tests-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-worker to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa
Upgrade
Upgrade redhat/osbuild-composer-worker-debuginfo to a version that resolves this vulnerability.
Fixed in 132.2-11.el9_6.aa

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

Frequently Asked Questions

Which components are covered by this update?

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

What types of security issues are addressed?

The update fixes three issues in golang.org/x/net/html: HTML parsing-bypass cross-site scripting, arbitrary code execution through cross-site scripting, and cross-site scripting caused by unexpected HTML tree rendering.

Does the advisory provide a temporary mitigation if the update cannot be installed immediately?

No temporary mitigation or configuration workaround is provided in the advisory data. The stated remediation is the osbuild-composer security update.

RHSA-2026:59560: Important: osbuild-composer security update

Other sources

Affected Software

Remediation

Event History

Frequently Asked Questions

Which components are covered by this update?

What types of security issues are addressed?

Does the advisory provide a temporary mitigation if the update cannot be installed immediately?

Company

Resources

Contact

Frequently Asked Questions

Which components are covered by this update?

What types of security issues are addressed?

Does the advisory provide a temporary mitigation if the update cannot be installed immediately?