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 Utility::copyInternetAddressAndPort and QUIC client-address paths reconstruct scoped IPv6 addresses through addressAsString and Ipv6Instance. The string includes a percent scope identifier that inet_pton cannot parse, causing an exception or abort. Kernel-provided scoped IPv6 destinations in ORIGINAL_DST transparent-proxy deployments, and affected QUIC connection paths, can therefore terminate the process. The relevant scope boundary is that the HTTP use_http_header override rejects scoped addresses earlier; the advisory's crash path requires a kernel-provided original destination or the affected QUIC path. 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 |