istio(1.26.4): Critical Bug Fixes for Gateway, Traffic Management, and Helm Chart Stability

📋 Recommended Actions ✅ No Immediate Action Required Upgrade recommended for improved stability and corrected behavior, especially for users of Istio Gateway API and mixed IPv4/IPv6 environments. 📝 Summary Istio 1.26.4 is here, delivering essential bug fixes and stability enhancements for your service mesh deployments. This patch release addresses a critical istio-iptables issue that previously ignored IPv4 state in mixed environments, ensuring more robust traffic interception for all users. We’ve also resolved a significant bug in the tag watcher, which now correctly handles defaultRevision logic, leading to more reliable Kubernetes Gateway programming. This means your gateways will function as expected without unexpected configuration discrepancies. For HTTP/1.x traffic, a subtle but important fix prevents PreserveHttp1HeaderCase from overriding other vital protocol options, maintaining precise control over your traffic. Additionally, we’ve updated the Gateway Helm chart schema to ensure full compatibility with Helm v3.18.5 and beyond, smoothing out installation processes. Numerous dependency updates, including Kubernetes client libraries, further bolster the mesh’s foundational stability. This release focuses on refining existing functionality and ensuring a more predictable and stable Istio experience. ...

September 3, 2025 · Daniel Grenemark

istio(1.26.2): OpenShift TPROXY Fixes and Gateway API Consistency Enhancements

📋 Recommended Actions ✅ No Immediate Action Required No immediate action required for most users. OpenShift users leveraging TPROXY mode should review the update for critical fixes. All Gateway API users should be aware of internal VirtualService naming changes for generated resources. 📝 Summary Istio 1.26.2 delivers targeted fixes and crucial consistency improvements, especially for OpenShift and Gateway API users. A significant bug has been resolved for OpenShift deployments utilizing TPROXY mode, which previously suffered from incorrect UID and GID assignments for sidecar containers. This fix ensures proper operation and security context enforcement. The release also brings enhanced robustness to Gateway API status reconciliation. Internal logic now intelligently compares desired and live states before writing, dramatically reducing redundant status updates and handling concurrent modifications more gracefully. This means a more stable control plane experience. Furthermore, the naming convention for auto-generated VirtualServices from HTTPRoutes has been refined for consistency, adopting a new scheme that directly reflects the merge key. While an internal detail, this can impact tools relying on generated resource names. Finally, internal integration tests gain greater flexibility with a new flag to control Gateway API deployment, alongside a fix for Kind cluster registry redirection. This patch release focuses on improving stability and correctness for specific deployment scenarios and advanced users. ...

June 20, 2025 · Daniel Grenemark