Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. Versions 1.34.0 through 1.34.4 and 1.35.0 contain a use-after-free (UAF) vulnerability in the DNS cache, causing abnormal process termination. The vulnerability is in Envoys Dynamic Forward Proxy implementation, occurring when a completion callback for a DNS resolution triggers new DNS resolutions or removes existing pending resolutions. This condition may occur when the following conditions are met: dynamic Forwarding Filter is enabled, the envoy.reloadable_features.dfp_cluster_resolves_hosts runtime flag is enabled, and the Host header is modified between the Dynamic Forwarding Filter and Router filters. This issue is resolved in versions 1.34.5 and 1.35.1. To work around this issue, set the envoy.reloadable_features.dfp_cluster_resolves_hosts runtime flag to false.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Envoy | Envoyproxy | 1.34.0 (including) | 1.34.5 (excluding) |
| Envoy | Envoyproxy | 1.35.0 (including) | 1.35.0 (including) |
| Red Hat OpenShift Service Mesh 3.0 | RedHat | openshift-service-mesh/istio-proxyv2-rhel9:sha256:bfb6528653e71c39a0c8b1ed5b47f470cdca34f19ea0fe97870ddf6e27b6e862 | * |