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wid-sec-w-2026-0704  ·  Published 2026-03-11  ·  View on BSI CERT-Bund ↗

Google Cloud Platform Envoy Proxy, Istio and Service Mesh: Multiple Vulnerabilities

CVSS 8.7 HIGH

Risk Summary

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, a logic vulnerability in Envoy's HTTP connection manager (FilterManager) that allows for Zombie Stream Filter Execution. This issue creates a "Use-After-Free" (UAF) or state-corruption window where filter callbacks are invoked on an HTTP stream that has already been logically reset and cleaned up. The vulnerability resides in source/common/http/filter_manager.cc within the FilterManager::decodeData method. The ActiveStream object remains valid in memory during the deferred deletion window. If a DATA frame arrives on this stream immediately after the reset (e.g., in the same packet processing cycle), the HTTP/2 codec invokes ActiveStream::decodeData, which cascades to FilterManager::decodeData. FilterManager::decodeData fails to check the saw_downstream_reset_ flag. It iterates over the decoder_filters_ list and invokes decodeData() on filters that have already received onDestroy(). This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13. Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, At the rate limit filter, if the response phase limit with apply_on_stream_done in the rate limit configuration is enabled and the response phase limit request fails directly, it may crash Envoy. When both the request phase limit and response phase limit are enabled, the safe gRPC client instance will be re-used for both the request phase request and response phase request. But after the request phase request is done, the inner state of the request phase limit request in gRPC client is not cleaned up. When a second limit request is sent at response phase, and the second limit request fails directly, the previous request's inner state may be accessed and result in crash. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

Affected Vendors

Amazon Google Red Hat

Affected Products (8)

Google · Cloud Platform Envoy Proxy
Google · Cloud Platform Istio
Google · Cloud Platform Service Mesh <1.28.5-asm.9
Google · Cloud Platform Service Mesh 1.28.5-asm.9
Google · Cloud Platform Service Mesh <1.27.8-asm.7
Google · Cloud Platform Service Mesh 1.27.8-asm.7
Google · Cloud Platform Service Mesh <1.26.8-asm.3
Google · Cloud Platform Service Mesh 1.26.8-asm.3

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