CVE-2025-30157

Envoy is a cloud-native high-performance edge/middle/service proxy. Prior to 1.33.1, 1.32.4, 1.31.6, and 1.30.10, Envoy's ext_proc HTTP filter is at risk of crashing if a local reply is sent to the external server due to the filter's life time issue. A known situation is the failure of a websocket handshake will trigger a local reply leading to the crash of Envoy. This vulnerability is fixed in 1.33.1, 1.32.4, 1.31.6, and 1.30.10.

Envoy is a cloud-native high-performance edge/middle/service proxy. Prior to 1.33.1, 1.32.4, 1.31.6, and 1.30.10, Envoy's ext_proc HTTP filter is at risk of crashing if a local reply is sent to the external server due to the filter's life time issue. A known situation is the failure of a websocket handshake will trigger a local reply leading to the crash of Envoy. This vulnerability is fixed in 1.33.1, 1.32.4, 1.31.6, and 1.30.10.

### Summary Envoy's ext_proc HTTP filter is at risk of crashing if a local reply is sent to the external server due to the filter's life time issue. A known situation is the fail of a websocket handshake will trigger a local reply leading to the crash of Envoy. ### PoC If both websocket and ext_proc are enabled, a failed handshake will trigger a local reply, thus ext_proc will crash. ### Mitigation 1. Disable websocket traffic 2. Change the websocket response from backend to always return `101 Switch protocol` based on RFC. 3. Apply the patch and the ext_proc filter will not send the local reply that is generated by Envoy to the ext_proc server for processing. 4. Apply the patch that the router will cancel the upstream requests when sending a local reply. ### Impact Denial of service ### Reporter Vasilios Syrakis Fernando Cainelli

### Summary Envoy's ext_proc HTTP filter is at risk of crashing if a local reply is sent to the external server due to the filter's life time issue. A known situation is the fail of a websocket handshake will trigger a local reply leading to the crash of Envoy. ### PoC If both websocket and ext_proc are enabled, a failed handshake will trigger a local reply, thus ext_proc will crash. ### Mitigation 1. Disable websocket traffic 2. Change the websocket response from backend to always return `101 Switch protocol` based on RFC. 3. Apply the patch and the ext_proc filter will not send the local reply that is generated by Envoy to the ext_proc server for processing. 4. Apply the patch that the router will cancel the upstream requests when sending a local reply. ### Impact Denial of service ### Reporter Vasilios Syrakis Fernando Cainelli

Envoy es un proxy de alto rendimiento para servicios perimetrales, intermedios y de borde, nativo de la nube. En versiones anteriores a las 1.33.1, 1.32.4, 1.31.6 y 1.30.10, el filtro HTTP ext_proc de Envoy corría el riesgo de bloquearse si se enviaba una respuesta local al servidor externo debido a un problema de duración del filtro. Un fallo en el protocolo de enlace websocket desencadenaba una respuesta local que provocaba el bloqueo de Envoy. Esta vulnerabilidad se corrigió en las versiones 1.33.1, 1.32.4, 1.31.6 y 1.30.10.