Medium · published September 22, 2026
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 HTTP external-authorization client can retain a stale request callback after a request is rejected. When RawHttpClientImpl::onSuccess later processes the authorization response, it can invoke callbacks_ after the callback owner has been destroyed, causing a use-after-free and process crash under production traffic. The relevant scope boundary is that the vulnerable path uses the HTTP ext_authz client; the advisory does not establish the same trigger for unrelated filters. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.
| Product | Versions | Fixed in |
|---|---|---|
| envoyproxy/envoy | < 1.36.10 | 1.36.10 |
| envoyproxy/envoy | ≥ 1.37.0, < 1.37.6 | 1.37.6 |
| envoyproxy/envoy | ≥ 1.38.0, < 1.38.4 | 1.38.4 |
| envoyproxy/envoy | ≥ 1.39.0, < 1.39.1 | 1.39.1 |