CVE-2025-30157: Envoy crashes when HTTP ext_proc processes local replies
### 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
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-30157?
CVE-2025-30157 has been classified with a high severity due to the risk of Envoy crashing under certain conditions.
How do I fix CVE-2025-30157?
To fix CVE-2025-30157, upgrade Envoy to version 1.33.1 or higher.
What versions of Envoy are affected by CVE-2025-30157?
CVE-2025-30157 affects Envoy versions prior to 1.33.1, 1.32.4, 1.31.6, and 1.30.10.
What is the nature of the vulnerability described in CVE-2025-30157?
CVE-2025-30157 involves a crashing issue in Envoy's ext_proc HTTP filter when a local reply is sent to an external server.
Is there a workaround for CVE-2025-30157?
Currently, the best practice is to upgrade the affected Envoy versions, as there are no effective workarounds documented.