CVE-2026-73512

High

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's HttpDatagramHandler caches the current RequestDecoder when Capsule Protocol is enabled. Stream recreation, including an internal redirect, replaces the ActiveStream and updates EnvoyQuicServerStream but does not update the handler's cached pointer. A subsequent HTTP/3 datagram can call decodeData through the freed decoder, causing invalid virtual dispatch and a process crash. The relevant scope boundary is that hTTP/3 datagrams and Capsule Protocol must be enabled, and the request must enter a stream-recreation path such as an internal redirect. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

SeverityHigh
CVSS7.5
Exploit probability—
ProductEnvoy
PublishedSep 21, 2026
First seenSep 21, 2026

How to fix

Update
  • envoyproxy envoy1.36.10, 1.37.6, 1.38.4, 1.39.1 or later

Affected products

ProductAffected versionsFixed in
envoyproxy envoyv < 1.36.10, 1.37.0 ≤ v < 1.37.6, 1.38.0 ≤ v < 1.38.4, 1.39.0 ≤ v < 1.39.11.36.10, 1.37.6, 1.38.4, 1.39.1

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