Istio

1.29.4Networking & Messaging

2026年6月5日リンクをコピー

Istio 1.29.4 patches a high-severity DoS CVE in Envoy plus six bug fixes, including a critical ambient mode traffic routing bug that could silently send traffic to unhealthy endpoints cluster-wide.

• securityPatch CVE-2026-47774 immediately — unauthenticated HTTP/2 DoS

  CVE-2026-47774 lets any unauthenticated attacker exhaust Envoy's memory via crafted HTTP/2 requests. Cookie header bytes aren't fully counted in header size validation, and HPACK limits apply only to encoded bytes — not decoded totals. If you're on 1.29.x, upgrade to 1.29.4 now. This is exploitable from outside the mesh wherever Envoy terminates HTTP/2, including ingress gateways.

• breakingAmbient mode users: audit Services using publishNotReadyAddresses + traffic distribution

  If any Service in your ambient mesh combines publishNotReadyAddresses:true with PreferSameZone or PreferSameNode traffic distribution, every other Service sharing that traffic-distribution preset was receiving healthPolicy:AllowAll — meaning traffic could route to not-ready endpoints across the entire cluster. After upgrading to 1.29.4, verify endpoint health policies are correct. Check ztunnel logs for unexpected AllowAll entries before and after the upgrade to confirm the fix took effect.

• enhancementCNI on older kernels: nftables fallback now automatic

  Hosts running an nft binary compiled without JSON support were causing the CNI agent to log errors and retry indefinitely on every pod removal — a silent drain on the agent's reliability. The new startup check detects this and switches to iptables automatically. No action needed for most users, but if you've been seeing 'JSON support not compiled-in' errors in CNI agent logs, this fix resolves the root cause.