RHSA-2026:27856HighCVSS 9.1

Red Hat Security Advisory: osbuild-composer security update

Published
June 22, 2026
Last Modified
October 3, 2026

🔗 CVE IDs covered (2)

CVE-2026-33186 →CVE-2026-34986 →

📋 Description

CVE-2026-33186 — google.golang.org/grpc/grpc-go: google.golang.org/grpc/authz: gRPC-Go: Authorization bypass due to improper HTTP/2 path validation CVE-2026-34986 — github.com/go-jose/go-jose/v3: github.com/go-jose/go-jose/v4: Go JOSE: Denial of Service via crafted JSON Web Encryption (JWE) object

🎯 Affected products30

  • Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-0:134.1-9.el10_0.src as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-debuginfo-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-debuginfo-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-debuginfo-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-core-debuginfo-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-debugsource-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-debugsource-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-debugsource-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-debugsource-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-tests-debuginfo-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-tests-debuginfo-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-tests-debuginfo-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-tests-debuginfo-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-debuginfo-0:134.1-9.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-debuginfo-0:134.1-9.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-debuginfo-0:134.1-9.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • osbuild-composer-worker-debuginfo-0:134.1-9.el10_0.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: To mitigate this issue, implement infrastructure-level normalization to ensure all incoming HTTP/2 `:path` headers are properly formatted with a leading slash before reaching the gRPC-Go server. This can be achieved by configuring a reverse proxy or API gateway to validate and normalize the `:path` header. Ensure that any such intermediary is properly configured and restarted to apply the changes, which may temporarily impact service availability. Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

🔗 References (5)