RHSA-2026:60391HighCVSS 9.9

Red Hat Security Advisory: Red Hat Advanced Cluster Management for Kubernetes v2.16.4 security update

Published
August 26, 2026
Last Modified
August 29, 2026

🔗 CVE IDs covered (42)

CVE-2026-73122 →CVE-2026-73834 →CVE-2026-46600 →CVE-2026-66792 →CVE-2026-70496 →CVE-2026-10090 →CVE-2026-41178 →CVE-2026-56852 →CVE-2026-66800 →CVE-2026-67567 →CVE-2026-71469 →CVE-2026-71474 →CVE-2026-66780 →CVE-2026-12143 →CVE-2026-27145 →CVE-2026-42151 →CVE-2026-55677 →CVE-2026-66798 →CVE-2026-70495 →CVE-2026-66781 →CVE-2026-66797 →CVE-2026-71468 →CVE-2026-71846 →CVE-2026-73137 →CVE-2026-18874 →CVE-2026-42502 →CVE-2026-64927 →CVE-2026-66793 →CVE-2026-72526 →CVE-2026-76827 →CVE-2026-66878 →CVE-2026-70398 →CVE-2026-71471 →CVE-2026-71473 →CVE-2026-72508 →CVE-2026-75485 →CVE-2026-47219 →CVE-2026-66805 →CVE-2026-71470 →CVE-2026-71472 →CVE-2026-71475 →CVE-2026-71845 →

📋 Description

CVE-2026-10090 — multicluster-operators-subscription: multicluster-operators-subscription: namespace edit user can deploy cluster-scoped ClusterRoleBinding and become cluster-admin via Application Subscription CVE-2026-12143 — form-data: form-data: Form field override via CRLF injection CVE-2026-18874 — volsync-addon-controller: volsync-addon-controller: annotation values rendered into YAML via text/template without escaping allows YAML injection into Subscription CVE-2026-27145 — crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries CVE-2026-41178 — github.com/open-telemetry/opentelemetry-go: go.opentelemetry.io/otel/baggage: go.opentelemetry.io/otel/propagation: OpenTelemetry-Go: Denial of Service via oversized baggage headers CVE-2026-42151 — github.com/prometheus/prometheus: Prometheus: Information disclosure of Azure OAuth client secret via config API CVE-2026-42502 — golang.org/x/net/html: golang: golang.org/x/net/html: Cross-Site Scripting via unexpected HTML tree rendering CVE-2026-46600 — golang.org/x/net/dns/dnsmessage: golang.org/x/net/dns/dnsmessage: Denial of Service via invalid DNS record parsing CVE-2026-47219 — find-my-way: find-my-way: Denial of Service vulnerability in HTTP/2 server CVE-2026-55677 — github.com/labstack/echo: Echo: Unauthorized Information Disclosure via URL Path Decoding Discrepancy CVE-2026-56852 — golang.org/x/text: golang.org/x/text: Denial of Service via invalid UTF-8 input CVE-2026-64927 — multicloud-operators-channel: multicloud-operators-channel: cross-namespace Secret and ConfigMap mutation via spec.secretRef.namespace confused deputy CVE-2026-66780 — submariner-operator: submariner-operator: flat broker trust model grants every spoke full CRUD on all endpoints, secrets, and endpointslices in broker namespace CVE-2026-66781 — submariner-operator: submariner-operator: IPsec PSK stored cleartext in Submariner CR spec CVE-2026-66792 — multicloud-operators-subscription: multicloud-operators-subscription: IsClusterAdmin() trusts user-settable annotations on managed clusters CVE-2026-66793 — governance-policy-addon-controller: governance-policy-addon-controller: arbitrary container image override via ManagedClusterAddOn annotation enables RCE on spoke CVE-2026-66797 — cluster-backup-operator: cluster-backup-operator: Velero Restore includes cluster-scoped RBAC resources with no exclusion — tampered backup yields hub cluster-admin CVE-2026-66798 — cluster-backup-operator: cluster-backup-operator: Restore.spec.hooks passed verbatim to Velero Restore — arbitrary command execution in restored pods CVE-2026-66800 — cluster-backup-operator: cluster-backup-operator: CleanupAll triggers unguarded cluster-wide mass-delete via operator ServiceAccount CVE-2026-66805 — console: console: stored DOM XSS via unescaped pod logs in document.write CVE-2026-66878 — multicloud-operators-subscription: multicloud-operators-subscription: FetchChannelReferences honours Channel.spec.secretRef.namespace enabling cross-namespace Secret exfiltration CVE-2026-67567 — multicloud-operators-subscription: multicloud-operators-subscription: HelmRelease chart applied with controller SA without GVK or namespace restriction CVE-2026-70398 — multicloud-integrations: multicloud-integrations: GitOpsCluster.spec.argoServer.argoNamespace writes spoke bearer tokens to attacker-chosen namespace CVE-2026-70495 — search-v2-operator: search-v2-operator: cluster-wide impersonate on users/groups shared across 4 pods grants hub system:masters CVE-2026-70496 — search-v2-operator: search-v2-operator: operator ClusterRole is cluster-admin equivalent via impersonate, RBAC write, CSR approve, and ManifestWork CVE-2026-71468 — acm-search-v2-api-rhel9: search-v2-api: Cross-user bearer-token reuse via global federation-config cache CVE-2026-71469 — acm-search-v2-api-rhel9: search-v2-api: Unbounded tokenReviews cache allows unauthenticated memory-exhaustion DoS CVE-2026-71470 — acm-search-v2-rhel9: search-v2-operator: Search CR imageOverride/arguments/envVar flow unsanitized into pods running impersonating SA CVE-2026-71471 — acm-search-v2-rhel9: search-v2-operator: Hub Search CR Collector.ImageOverride propagated to every spoke as arbitrary container image CVE-2026-71472 — acm-search-v2-rhel9: search-v2-operator: Shell-command and SQL injection in postgresql-start.sh via CR-supplied WORK_MEM CVE-2026-71473 — acm-search-v2-rhel9: search-v2-operator: addonfactory.GetValuesFromAddonAnnotation enables arbitrary Helm-values override per spoke CVE-2026-71474 — insights-client-rhel9: insights-client: Pull-secret bearer token written to logs on non-200 CCX response CVE-2026-71475 — insights-client-rhel9: insights-client: Spoke-controlled ClusterID injected unencoded into Insights API URL path CVE-2026-71845 — insights-client: insights-client: CCX_TOKEN bearer credential logged in clear text at startup via setDefault() CVE-2026-71846 — insights-client: insights-client: ClusterRole grants cluster-wide secrets get/list/watch beyond least privilege CVE-2026-72508 — multicloud-operators-subscription: multicloud-operators-subscription: hub and spoke ServiceAccounts bound to wildcard RBAC (//*) CVE-2026-72526 — multicloud-integrations: multicloud-integrations: pull-model propagation allows hub tenant to target arbitrary spoke cluster via unvalidated ocm-managed-cluster annotation CVE-2026-73122 — multicloud-operators-channel: multicloud-operators-channel: auto-generated Role grants every managed-cluster agent secrets:get,list,watch in Channel namespaces CVE-2026-73137 — multicloud-operators-subscription: multicloud-operators-subscription: cross-namespace Secret exfiltration via HelmRelease.repo.secretRef.namespace CVE-2026-73834 — must-gather: must-gather: embedded Secret data in ACM wrapper CRs collected without redaction CVE-2026-75485 — must-gather: must-gather: cluster Proxy object dumped raw, bypassing inspect redaction of proxy basic-auth credentials CVE-2026-76827 — search-indexer: search-indexer: UPDATE/DELETE operations not scoped to caller's cluster (cross-tenant data tampering)

🎯 Affected products189

  • Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cli-rhel9@sha256:1256ae2cb875150cb331b7e42c73c83f3a87efdb59a9c75f691068cf0d377a3d_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cli-rhel9@sha256:1cf15ce15e016c7d19a2dbad16a0c05730b7c1adc6c731cb952c80796a09b109_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cli-rhel9@sha256:5132e9c25bfa0ac763ec581295eba8833ff22c1cf9d3e0c801daa99a4329407e_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cli-rhel9@sha256:6c3d3e358287ff955a6fab54274956da72067bdf0d0e2451b6eed96c7fd2ba3a_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cluster-permission-rhel9@sha256:13a315926e0fe55f86c3ab8d4b419c38fb5d3c3613555582679a8913d532b075_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cluster-permission-rhel9@sha256:329695fd2166e65f7015629cea32e470034fea240f6cd23d5a4af970e2153133_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cluster-permission-rhel9@sha256:459de12302a2f9d7681845d8c6d91e5d29ae6477a3d7ee2fa837ea34716078c9_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-cluster-permission-rhel9@sha256:e54ffd60c9a728d6f6c102509964f898518b3a967e3871a0dda97242b66e8279_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-addon-controller-rhel9@sha256:149838709f1fd62534ebb5d175b0e0ba4035b1c89aa3afb2a37943448bcb371e_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-addon-controller-rhel9@sha256:223265ea583a448d4fda8bdd96daf283a94c8e7a2f8d346a3a3c6e8484d62acf_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-addon-controller-rhel9@sha256:75d8599c64a15927af46663f6939cb2e2fbac28ade8f35be895b1c9ac88f94e6_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-addon-controller-rhel9@sha256:9b710c6db4d80628c3db5e01ffbfe1875d07ecbb66490ff64e183db81b1ed904_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-framework-addon-rhel9@sha256:5f34d123d8c63286c2761555d8c5be4255567ec2cc0235979745780f9bcf9b59_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-framework-addon-rhel9@sha256:694f80aea01eb865e9d984fbd12889b68649849dc3643ac311de6bd47fe77f99_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-framework-addon-rhel9@sha256:87c49074e55199085bf27585c452f2c5eb4b498fc143daa4a5d4d48705e3a7ae_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-governance-policy-framework-addon-rhel9@sha256:fda7afaec72c13b9200bb9559cf6586a84c37a3e1105199cb6564936d31c8f8a_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-grafana-rhel9@sha256:47779227c5822a9d5f081d1a04f086d4ea6599d271b147ead213e552ec11cabc_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-grafana-rhel9@sha256:8da852d7ccdcf7a133d9fc2b24f88cf68b92efc8537b0261f74748748979888d_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-grafana-rhel9@sha256:dc20a660f506c835c393756d69e8ca0896c59a363b7728222e78d93f008d4313_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-grafana-rhel9@sha256:e7ce9123cfafde180faa177c04e631c83942882398f80c9bd820a80986905ba6_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-multicluster-observability-addon-rhel9@sha256:46549b2fd8c26aace313716bc21b9ad99c863f747c15867fbdd9030f5132b944_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-multicluster-observability-addon-rhel9@sha256:6a649091c21725f736d43871b1c1ad9042c029224a6bdb72911400e2e4a0d812_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-multicluster-observability-addon-rhel9@sha256:7c4db7ec0135203c260e31bfa6e0eaf6eda008f0dc8020fd22040ce795f85d76_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-multicluster-observability-addon-rhel9@sha256:f1ee9f8dd677970269781efa5b1305588f2cdd61098266c5de1aae3c67a92041_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-must-gather-rhel9@sha256:46eb950072c37c25093cc114c08563e851f2358f184638f57060db2e1b4bbc31_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-must-gather-rhel9@sha256:5e4914b26e35928ead59dbc026ab77cc685aa8ca23db4f0f2189beba0e1d2514_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-must-gather-rhel9@sha256:6c9d1cd1d9cff40ac9560393ab966e77fbde06c10e24dd18c8b41dc8d92633f0_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-must-gather-rhel9@sha256:c310819b9413afc0d4e0fa67845d214354130a85929d797e20779cf911c2c253_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • registry.redhat.io/rhacm2/acm-prometheus-config-reloader-rhel9@sha256:11cfe441966b2d63d1ddb57cddf8ab46dfb4ecaaf0010868f9a080e21e47a3e4_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.16
  • +159 more not shown

✅ Remediation

Before you apply this update, make sure all previously released errata that are relevant to your system are applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 Workaround: Remove the RBAC aggregation (immediate, targeted) Delete the ClusterRole that aggregates Application Subscription management permissions into the Kubernetes edit role: oc delete clusterrole open-cluster-management:multicloud-operators-subscription:rbac-aggregate-edit Verification: oc auth can-i create subscriptions.apps.open-cluster-management.io --as=<user> -n <namespace> Expected result after mitigation: no Important notes: This ClusterRole is recreated by the multiclusterhub-operator during reconciliation. Customers must re-apply this mitigation after any ACM operator upgrade, operator pod restart, or MultiClusterHub CR modification until a fixed release is installed. After deletion, users with only the edit or view roles will no longer be able to create or delete Application Subscription, Channel, or related resources. Users who are bound to open-cluster-management:subscription-admin or who have explicit RBAC grants are unaffected. Existing Application Subscriptions continue to function normally. Workaround: Applications using the `form-data` library should implement strict input validation and sanitization for all field names and filenames derived from untrusted sources. This prevents the injection of control characters (CR, LF, ") that could lead to header injection or form field overrides. Deployments that exclusively use fixed or trusted field names are not impacted. Workaround: To mitigate this vulnerability, ensure that the `volsync-addon-deploy-type` annotation is not explicitly set to `olm`. The default Helm deployment type for volsync-addon-controller in Red Hat Advanced Cluster Management for Kubernetes (since ACM 2.13) is not affected by this flaw. Workaround: A flaw was found in the Go standard library crypto/x509 package. When verifying a TLS certificate hostname, VerifyHostname processed each DNS Subject Alternative Name (SAN) entry in a loop and repeatedly split the candidate hostname on "." characters. For certificates with a very large DNS SAN list, CPU use could grow quadratically with the number of SAN entries and hostname labels. Because hostname verification runs before the certificate chain is built, this overhead can occur even when the certificate is not trusted. Red Hat rates this issue as Important. It affects Red Hat products that include the Go standard library crypto/x509 code from an affected Go toolchain version (before Go 1.25.11, or from Go 1.26.0 through Go 1.26.3). Applications and container images built with a fixed Go release (1.25.11 or later, or 1.26.4 or later) are not affected. Community distributions such as Fedora are also affected. Upstream fix: Go 1.25.11 and Go 1.26.4 (GO-2026-5037). Workaround: Applications utilizing `golang.org/x/net/html` should implement robust sanitization of all untrusted HTML input before rendering to prevent the creation of unexpected HTML structures that could facilitate XSS attacks. If an application does not require rendering arbitrary HTML, it should avoid processing such input. Workaround: There is no available mitigation for this flaw other than updating the bundled find-my-way library to a fixed version (9.7.0 or later). Where feasible, restricting the affected service to HTTP/1.1 (disabling HTTP/2) removes the attack vector, since the flaw is only reachable through the HTTP/2 request path. 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. Workaround: Restrict the creation of `Channel` resources to trusted administrators within Red Hat Advanced Cluster Management. This limits the attack surface by preventing unauthorized tenants from exploiting the confused deputy vulnerability in the `multicloud-operators-channel` component. Workaround: To mitigate the risk of IPsec pre-shared key (PSK) disclosure, implement strict Kubernetes Role-Based Access Control (RBAC) policies to limit access to Submariner Custom Resources. Ensure that only authorized administrators and systems are granted permissions to view `submariner` Custom Resources within their namespaces. Additionally, exercise caution when collecting and storing diagnostic data, such as must-gather bundles, and when managing GitOps repositories, as these may inadvertently expose the cleartext PSK. Workaround: To mitigate this issue, restrict users' ability to annotate ManagedClusterAddOn resources within the hub cluster. Ensure that only trusted administrators have namespace-level annotate permissions on these resources. Regularly review and audit permissions related to ManagedClusterAddOn resources to prevent unauthorized modifications. If a service is restarted or reloaded, these permission changes will persist. Workaround: Restrict access to the backup storage location (e.g., S3 bucket) to authorized personnel only. Implement strict Role-Based Access Control (RBAC) to limit which users or service accounts can create Velero Backup objects within the open-cluster-management-backup namespace. This prevents an attacker from injecting malicious ClusterRoleBindings into backups or referencing untrusted backup objects. Ensure that only trusted and verified backups are used for restore operations. Workaround: To mitigate this issue, ensure that only highly trusted administrators are granted `namespace-admin` privileges within the `open-cluster-management-backup` namespace. This restricts the ability to create or modify `Restore` Custom Resources with malicious hooks, thereby preventing arbitrary command execution in restored pods. Workaround: To reduce the risk of exploitation, ensure strict access controls are enforced on managed clusters, limiting the ability of untrusted users to deploy or modify pods and thus inject malicious content into container logs. Additionally, users should exercise caution when viewing "Raw" logs from potentially untrusted sources within the hub console. Workaround: To mitigate this issue, restrict the ability of untrusted tenants to create `HelmRelease` custom resources within the cluster. Implement strict Role-Based Access Control (RBAC) policies to limit which users or service accounts can create or modify `HelmRelease` objects. This will prevent unauthorized users from leveraging the controller's elevated privileges for cluster-wide resource deployment. Workaround: To mitigate this issue, ensure that the `FEATURE_FEDERATED_SEARCH` is not enabled if federated search functionality is not required. This feature is disabled by default in Red Hat Advanced Cluster Management for Kubernetes. If `FEATURE_FEDERATED_SEARCH` is enabled, consider disabling it to prevent unauthorized cross-user data access. Disabling this feature will impact the ability to perform federated searches across managed hubs. Workaround: To mitigate this issue, restrict network access to the `search-v2-api` component within Red Hat Advanced Cluster Management for Kubernetes. Implement network policies to limit incoming connections to only trusted sources that require access to the search API. This will reduce the attack surface for unauthenticated denial-of-service attempts. After applying network policies, ensure that the `search-v2-api` pod is restarted to apply the new network rules effectively. Workaround: To mitigate this issue, restrict permissions for creating and modifying Search Custom Resources (CRs) to only trusted and authorized users. Implement Kubernetes Role-Based Access Control (RBAC) policies to limit who can perform `create`, `update`, and `patch` operations on `search.search.open-cluster-management.io` resources. This reduces the attack surface by preventing unauthorized use…

🔗 References (46)