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CVE-2026-47205

Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides

5.9 MediumFix available

CVE-2026-47205 is a medium vulnerability (CVSS 5.9) in Envoyproxy Envoy, published June 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 32nd percentile. Fixed in envoy 1.36.9.

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.39%Unchanged since Jun 27, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.9

Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides

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.

Record
CVE-2026-47205
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
EUVDEUVD-2026-39828 5.9

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.

Record
EUVD-2026-39828
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
NVD 5.9

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.

Record
CVE-2026-47205
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
OSV 5.9

Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides

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.

Record
CVE-2026-47205
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-416
Updated
2026-11-02
OSVBIT-envoy-2026-47205 No score

Envoy: ext_authz Use-After-Free during Stream Teardown with Per-Route Overrides

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.

Record
BIT-envoy-2026-47205
Updated
2026-11-02
OSVopenSUSE-SU-2026:11141-1 No score

istioctl-1.30.2-1.1 on GA media

These are all security issues fixed in the istioctl-1.30.2-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11141-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
envoy
Bitnami
1.36.0 up to 1.36.9, 1.37.0 up to 1.37.5, 1.38.0 up to 1.38.3
1.36.91.37.51.38.3
istioctl
openSUSE:Tumbleweed
before 1.30.2-1.1
1.30.2-1.1

History

History
WhenChangedSources
2026-11-02aliases, publishedEUVD
2026-11-02createdCVE List, NVD, OSV

References

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