CVE-2026-48521

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 ProdClusterManagerFactory::allocateConnPool dereferences transport_socket_options while selecting an HTTP/3 connection pool without first checking whether the pointer is null. LoadBalancerContext implementations used by synthetic, mirror, health-check, and async-client calls can return no transport-socket options. With auto_config and HTTP/3 enabled, routine traffic reaching one of those contexts can crash an Envoy worker. The relevant scope boundary is that the affected branch requires HTTP/3 in the protocol set and a context that supplies no transport-socket options. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

• https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868Patch
• https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96Patch
• https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7Patch
• https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45aPatch
• https://github.com/envoyproxy/envoy/releases/tag/v1.36.10Release Notes
• https://github.com/envoyproxy/envoy/releases/tag/v1.37.6Release Notes
• https://github.com/envoyproxy/envoy/releases/tag/v1.38.4Release Notes
• https://github.com/envoyproxy/envoy/releases/tag/v1.39.1Release Notes
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3Exploit
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3Exploit