CVE-2026-47205
Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides
Description
Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.36.0 until 1.36.9, 1.37.5, and 1.38.3, a Use-After-Free (UAF) vulnerability leading to a sudden segmentation fault exists in Envoy's ext_authz HTTP filter when processing per-route authorization overrides concurrently with rapid downstream client disconnects. During standard request lifecycles, Envoy instantiates the ext_authz filter with a foundational authorization client object (client_). If a matched route dictates a dynamic per-route HTTP or gRPC authorization service override, the filter generates a localized client. In the vulnerable implementation, this transient client aggressively overwrote the default client_ unique pointer by executing client_ = std::move(per_route_client). When a client rapidly establishes and subsequently tears down a stream (such as rapidly refreshing a protected WebSocket endpoint), the downstream triggers the ConnectionManagerImpl::doDeferredStreamDestroy() -> ActiveStream::onResetStream() lifecycle. Envoy immediately sequences Filter::onDestroy() in an attempt to securely abort dispatched asynchronous authorization check transactions via client_->cancel(). By destructing the default client abruptly during initiateCall, a memory lifecycle misalignment occurs within the async client manager. The stream teardown fails to reliably track and cancel the dynamically bound asynchronous authorization tasks, orchestrating a sequence where a late asynchronous callback from the network evaluates against a heavily destroyed ActiveStream validation span, generating a UAF process crash. This vulnerability is fixed in 1.36.9, 1.37.5, and 1.38.3.
INFO
Published Date :
June 26, 2026, 7:16 p.m.
Last Modified :
Oct. 25, 2026, 5:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Envoy to version 1.36.9 or later.
- Update Envoy to version 1.37.5 or later.
- Update Envoy to version 1.38.3 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-47205.
| URL | Resource |
|---|---|
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j | Vendor Advisory Exploit Mitigation |
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j | Vendor Advisory Exploit Mitigation |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-47205 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-47205
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-47205 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-47205 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: envoy de envoyproxy, Description: Envoy es un proxy de borde y de servicio de código abierto diseñado para aplicaciones nativas de la nube. Desde 1.36.0 hasta 1.36.9, 1.37.5 y 1.38.3, existe una vulnerabilidad de uso después de liberación (UAF) que conduce a un fallo de segmentación repentino en el filtro HTTP ext_authz de Envoy al procesar anulaciones de autorización por ruta concurrentemente con desconexiones rápidas de clientes descendentes. Durante los ciclos de vida de solicitud estándar, Envoy instancia el filtro ext_authz con un objeto cliente de autorización fundamental (client_). Si una ruta coincidente dicta una anulación dinámica del servicio de autorización HTTP o gRPC por ruta, el filtro genera un cliente localizado. En la implementación vulnerable, este cliente transitorio sobrescribió agresivamente el puntero único client_ predeterminado al ejecutar client_ = std::move(per_route_client). Cuando un cliente establece y posteriormente cierra rápidamente un flujo (como al actualizar rápidamente un punto final WebSocket protegido), el descendente activa el ciclo de vida ConnectionManagerImpl::doDeferredStreamDestroy() -> ActiveStream::onResetStream(). Envoy secuencia inmediatamente Filter::onDestroy() en un intento de abortar de forma segura las transacciones de verificación de autorización asíncronas despachadas a través de client_ -> cancel(). Al destruir el cliente predeterminado abruptamente durante initiateCall, se produce un desajuste del ciclo de vida de la memoria dentro del gestor de clientes asíncronos. El cierre del flujo no logra rastrear y cancelar de forma fiable las tareas de autorización asíncronas vinculadas dinámicamente, orquestando una secuencia en la que una devolución de llamada asíncrona tardía de la red se evalúa contra un lapso de validación de ActiveStream fuertemente destruido, generando un fallo de proceso por UAF. Esta vulnerabilidad se corrige en 1.36.9, 1.37.5 y 1.38.3. -
Initial Analysis by [email protected]
Jun. 29, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions from (including) 1.37.0 up to (excluding) 1.37.5 *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions from (including) 1.38.0 up to (excluding) 1.38.3 *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions from (including) 1.36.0 up to (excluding) 1.36.9 Added Reference Type GitHub, Inc.: https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j Types: Exploit, Mitigation, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 27, 2026
Action Type Old Value New Value Added Reference https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j Added SSVC {'id': 'CVE-2026-47205', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-27T02:54:07.255044Z'} -
New CVE Received by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'envoyproxy', 'product': 'envoy', 'versions': [{'status': 'affected', 'version': '>= 1.38.0, < 1.38.3'}, {'status': 'affected', 'version': '>= 1.37.0, < 1.37.5'}, {'status': 'affected', 'version': '>= 1.36.0, < 1.36.9'}]}] Added Description Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.36.0 until 1.36.9, 1.37.5, and 1.38.3, a Use-After-Free (UAF) vulnerability leading to a sudden segmentation fault exists in Envoy's ext_authz HTTP filter when processing per-route authorization overrides concurrently with rapid downstream client disconnects. During standard request lifecycles, Envoy instantiates the ext_authz filter with a foundational authorization client object (client_). If a matched route dictates a dynamic per-route HTTP or gRPC authorization service override, the filter generates a localized client. In the vulnerable implementation, this transient client aggressively overwrote the default client_ unique pointer by executing client_ = std::move(per_route_client). When a client rapidly establishes and subsequently tears down a stream (such as rapidly refreshing a protected WebSocket endpoint), the downstream triggers the ConnectionManagerImpl::doDeferredStreamDestroy() -> ActiveStream::onResetStream() lifecycle. Envoy immediately sequences Filter::onDestroy() in an attempt to securely abort dispatched asynchronous authorization check transactions via client_->cancel(). By destructing the default client abruptly during initiateCall, a memory lifecycle misalignment occurs within the async client manager. The stream teardown fails to reliably track and cancel the dynamically bound asynchronous authorization tasks, orchestrating a sequence where a late asynchronous callback from the network evaluates against a heavily destroyed ActiveStream validation span, generating a UAF process crash. This vulnerability is fixed in 1.36.9, 1.37.5, and 1.38.3. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-416 Added Reference https://github.com/envoyproxy/envoy/security/advisories/GHSA-mvh9-767w-x47j