RHSA-2026:18068HighCVSS 9.1

Red Hat Security Advisory: Red Hat build of MicroShift 4.18.42 security update

Published
May 20, 2026
Last Modified
July 27, 2026

🔗 CVE IDs covered (1)

CVE-2026-33186 →

📋 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

🎯 Affected products19

  • Red Hat OpenShift Container Platform 4.18
  • microshift-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.aarch64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.src as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.x86_64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-gateway-api-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.aarch64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-gateway-api-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.x86_64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-gateway-api-release-info-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-greenboot-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-low-latency-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-multus-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.aarch64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-multus-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.x86_64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-multus-release-info-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-networking-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.aarch64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-networking-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.x86_64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-olm-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.aarch64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-olm-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.x86_64 as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-olm-release-info-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-release-info-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18
  • microshift-selinux-0:4.18.42-202605181217.p0.gf4eeb37.assembly.4.18.42.el9.noarch as a component of Red Hat OpenShift Container Platform 4.18

✅ Remediation

For MicroShift 4.18, read the following documentation for important instructions on how to install the latest RPMs and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/red_hat_build_of_microshift/4.18/html/red_hat_build_of_microshift_release_notes/index 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.

🔗 References (6)