CVE-2026-73512

7.5 HIGHpublic exploit available

Published 2026-09-21 · Updated 2026-09-21

AI risk analysis

Summary: The flaw allows HTTP/3 datagrams to call decodeData through a freed decoder, causing process crashes. It matters because it can lead to service disruptions and security vulnerabilities.
Exploitability: Exploitation requires enabling Capsule Protocol and HTTP/3 with specific stream recreation conditions; difficult but feasible for attackers targeting affected versions.
Blast radius: If exploited, could cause significant service downtime and impact cloud-native applications using Envoy proxies.
Prioritized remediation: Upgrade to Envoy versions 1.36.10, 1.37.6, 1.38.4, or 1.39.1 immediately to mitigate the risk.

proxyhttp3capsuleprotocolcrashservice

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD 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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses

CWE-416

Public exploit & PoC references

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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