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CVE-2026-47205— Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides

Quick assessment

Affected
envoyproxy envoy
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Envoy Proxy Envoy是Envoy Proxy团队的应用网关。 Envoy Proxy Envoy 1.36.0至1.36.9之前版本、1.37.0至1.37.5之前版本和1.38.0至1.38.3之前版本存在资源管理错误漏洞，该漏洞源于ext_authz HTTP过滤器中处理每条路由授权覆盖时与快速下游客户端断开连接时的内存生命周期错位，可能导致释放后重用漏洞，引发进程崩溃。

CVSS 5.9 · Medium EPSS 0.39% · P30

Possible ATT&CK Techniques 1 AI

T1211 · Exploitation for Stealth

Affected Version Matrix 3

VendorProduct Version RangeStatus
envoyproxy envoy >= 1.38.0, < 1.38.3 affected
>= 1.37.0, < 1.37.5 affected
>= 1.36.0, < 1.36.9 affected
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I. Basic Information for CVE-2026-47205

Vulnerability Information
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Vulnerability Title
Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5
Vulnerability Title
Envoy Proxy Envoy 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Envoy Proxy Envoy是Envoy Proxy团队的应用网关。 Envoy Proxy Envoy 1.36.0至1.36.9之前版本、1.37.0至1.37.5之前版本和1.38.0至1.38.3之前版本存在资源管理错误漏洞，该漏洞源于ext_authz HTTP过滤器中处理每条路由授权覆盖时与快速下游客户端断开连接时的内存生命周期错位，可能导致释放后重用漏洞，引发进程崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
envoyproxy envoy >= 1.38.0, < 1.38.3 -

II. Public POCs for CVE-2026-47205

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III. Intelligence Information for CVE-2026-47205

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Vendor Advisories for CVE-2026-47205 (1)

Same Patch Batch · envoyproxy · 2026-06-26 · 14 CVEs total

CVE-2026-48743 7.5 HIGH Envoy: HTTP/3 to HTTP/1 request smuggling via headers-only request with nonzero Content-Le
CVE-2026-48042 7.5 HIGH Envoy: Stack overflow in destructor of highly nested JSON
CVE-2026-48044 7.5 HIGH Envoy Zstd Decompressor: Ratio Check at Wrong Loop Depth lead to memory explosion
CVE-2026-47220 7.5 HIGH Envoy: Segmentation fault when using %REQUESTED_SERVER_NAME% in log format
CVE-2026-47775 6.8 MEDIUM Envoy OAuth2 Filter: Padding Oracle via AES-256-CBC Cookie Decryption
CVE-2026-47204 6.5 MEDIUM Envoy: grpc_stats filter segfault on Connect protocol requests to direct_response routes
CVE-2026-47207 6.5 MEDIUM Envoy crashes if multiple unexpected ext_proc responses are packed into one gRPC message
CVE-2026-47221 5.9 MEDIUM Envoy: Null pointer deref in internal redirects
CVE-2026-48497 5.9 MEDIUM Envoy: Abnormal process termination in DNS UDP filter
CVE-2026-48706 5.9 MEDIUM Envoy Heap Buffer Overflow in TcpStatsdSink
CVE-2026-48090 5.9 MEDIUM Envoy HTTP: OAuth2 filter late async token completion after stream teardown (UAF / crash r
CVE-2026-47692 4.8 MEDIUM Envoy: PROXY Protocol v2 header generator emits "skipped" TLVs, causing 65 KB attacker-con
CVE-2026-47778 4.4 MEDIUM Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (A

IV. Related Vulnerabilities

Same product: envoy
Same vendor: envoyproxy
Same weakness: CWE-416

V. Comments for CVE-2026-47205

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