CVE-2026-73512

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.9% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-08-12 19:00 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-09-21 20:17 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-05 14:12 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.9% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-21 20:17 UTC

Last modified

2026-10-05 14:12 UTC

Exploit probability

0.9% · EPSS, next 30 days

Weakness

CWE-416 · Use after free

Record status

Analyzed

Affected

• Envoyproxy Envoy < 1.36.10
• Envoyproxy Envoy < 1.37.6
• Envoyproxy Envoy < 1.38.4
• Envoyproxy Envoy < 1.39.1

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-73512.md and follow it. Check whether this project is affected by CVE-2026-73512. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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