Daily Digest
User Safety: safe
The most urgent item this cycle is CVE-2026-83711, a CVSS 10.0 authorization bypass in Microsoft Azure Active Directory B2C that allows a network-reachable attacker to elevate privileges without authentication—this perfect-score flaw outranks all other entries and should be patched immediately.
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Summary: IBM Instana Agent Operator (Build 1.0.303–1.0.323) suffers a namespace-silo failure where cluster-scoped RBAC objects are keyed solely by the CustomResource name, with no namespace disambiguation. An authenticated tenant in an attacker-controlled namespace can create a same-named `InstanaAgent` CR to silently overwrite or delete the shared `ClusterRoleBinding`, permanently revoking the victim agent's cluster monitoring access.
Affected Features / Interoperability: Cluster-wide RBAC permissions, multi-tenant Instana monitoring deployments, any integrations relying on continuous cluster-level observability.
Source: https://www.ibm.com/support/pages/node/7286070
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Summary: Red Hat Advanced Cluster Management (ACM) app-subscription controller fetches and applies Helm chart contents with elevated controller authority without verifying that the subscription creator holds the `subscription-admin` role. A namespace-scoped user with only "edit" privileges can include cluster-scoped resources (e.g., a `ClusterRoleBinding` granting `cluster-admin`) in a crafted Helm chart, achieving full cluster privilege escalation.
Affected Features / Interoperability: ACM multicluster application distribution, cross-namespace Helm release automation, hub-cluster governance workflows.
Source: https://access.redhat.com/errata/RHSA-2026:60386 (and RHSA-2026:60387–60390)
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Summary: The Amazon EFS CSI Driver before v3.3.4 does not verify that the filesystem ID in a `PersistentVolume`'s `volumeHandle` matches the access point's parent filesystem. An authenticated Kubernetes user with `PersistentVolume` creation privileges can pair an access point from one EFS filesystem with a different target filesystem, causing recursive directory deletion on filesystems they are not authorized to access.
Affected Features / Interoperability: EFS-backed `PersistentVolumeClaim` provisioning, storage classes using AWS EFS, any workload relying on EFS for shared storage across namespaces.
Source: https://aws.amazon.com/security/security-bulletins/2026-099-aws/ | https://github.com/kubernetes-sigs/aws-efs-csi-driver/releases/tag/v3.4.1
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Summary: Open Cluster Management (OCM), the underlying technology for Red Hat ACM, does not properly validate Kubernetes client certificate renewal. A managed cluster administrator can forge a client certificate that the OCM controller will approve, enabling cross-cluster privilege escalation and potential takeover of other managed clusters including the hub.
Affected Features / Interoperability: Hub-managed cluster registration, multicluster fleet management, cross-cluster authentication trusts.
Source: https://access.redhat.com/errata/RHSA-2026:11414 (and RHSA-2026:8218, 9848, 13542, 13853)
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Summary: Elastic Cloud on Kubernetes (ECK) stores Fleet Server's Elasticsearch service account token in cleartext within the workload specification instead of referencing it from the managed Secret. Any principal able to read workload specs in the affected namespace can retrieve a live Elasticsearch credential, bypassing Kubernetes RBAC protections on Secrets.
Affected Features / Interoperability: Elastic Fleet Server deployments, Elasticsearch client authentication, any ECK-managed Elastic Stack components sharing the namespace.
Source: https://discuss.elastic.co/t/elastic-cloud-on-kubernetes-3-5-0-security-update-esa-2026-113/389493
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Summary: ECK's incorrect authorization allows a namespace-constrained actor to inject attacker-controlled certificate material into the Elasticsearch client trust bundle managed by ECK in a separate namespace, enabling certificate-based metadata spoofing.
Affected Features / Interoperability: Elasticsearch mutual TLS authentication, ECK-managed trust bundle across namespaces, cross-namespace certificate provisioning.
Source: https://discuss.elastic.co/t/elastic-cloud-on-kubernetes-3-5-0-security-update-esa-2026-145/390105
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Summary: Traefik v3.7.0–v3.7.10 mishandles TLS option naming for Kubernetes Ingress objects with `nginx.ingress.kubernetes.io/auth-tls-secret` annotations. When two Ingress objects share the same host, CA secret, and client-auth mode, Traefik generates conflicting TLS option names and falls back to the entry point's default TLS configuration, which does not require client certificates. This silently bypasses mTLS enforcement configured on the Ingress.
Affected Features / Interoperability: Ingress NGINX `auth-tls` annotations, mTLS enforcement via Ingress, Traefik v3.7.x deployments relying on client certificate verification for secured routes.
Source: https://github.com/traefik/traefik/security/advisories/GHSA-j994-9gqj-9hwq | https://www.vulncheck.com/advisories/traefik-3.7-authentication-bypass-via-tls-option-conflict
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Summary: Microsoft Azure Active Directory B2C contains an authorization bypass through user-controlled key, allowing an unauthorized attacker to elevate privileges over the network without prior authentication. This flaw enables complete account takeover.
Affected Features / Interoperability: Azure AD B2C tenant configurations, user flows relying on custom key-based authorization, any application integrating B2C for identity and access management.
Source: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83711
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Summary: Moby/Docker Engine prior to 29.5.1 (and moby/moby v2 prior to v2.0.0-beta.14) resolves decompression binaries from the container's filesystem rather than the host's when processing compressed archives via `PUT /containers/{id}/archive` or `docker cp -`. A malicious container image containing a trojanized decompressor (e.g., `xz`, `unpigz`) can achieve arbitrary code execution with full daemon privileges and host root UID when a user uploads a compressed archive into that container.
Affected Features / Interoperability: `docker cp` with compressed archives, container image building and distribution, any workflow uploading compressed archives into containers.
Source: https://github.com/moby/moby/security/advisories/GHSA-x86f-5xw2-fm2r | https://access.redhat.com/errata/RHSA-2026:37387
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Summary: Google Cloud Integration Connectors contained a missing authorization flaw in the HTTP Connector. An authenticated user could escalate privileges and take over a Google Cloud Project by attaching an unauthorized service account via a specially crafted connector configuration. This was patched on 11 December 2025; no customer action is required.
Affected Features / Interoperability: GCP Integration Connectors (HTTP Connector), service account attachment workflows, cross-project connector configurations.
Source: https://docs.google.com/support/bulletins#gcp-2026-059
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Summary: HashiCorp go-slug versions 0.4.0 through 0.18.2 improperly handles Unicode normalization during path matching, allowing a local attacker to bypass `.terraformignore` exclusions and cause sensitive files to be included in Terraform slug uploads.
Affected Features / Interoperability: Terraform Enterprise/Cloud slug upload functionality, any workflow relying on `.terraformignore` to exclude sensitive files from state or configuration bundles.
Source: https://www.ibm.com/support/pages/node/7284170
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