CVE-2026-47205 (GCVE-0-2026-47205)
Vulnerability from cvelistv5 – Published: 2026-06-26 18:01 – Updated: 2026-06-27 02:54
VLAI
EPSS
VEX
Title
Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides
Summary
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.
Severity
5.9 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-27 02:54 UTC
CWE
- CWE-416 - Use After Free
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/envoyproxy/envoy/security/advi… | x_refsource_CONFIRM |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| envoyproxy | envoy |
Affected:
>= 1.38.0, < 1.38.3
Affected: >= 1.37.0, < 1.37.5 Affected: >= 1.36.0, < 1.36.9 |
guessed |
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