1.27.1 (October 11, 2023)

Incompatible behavior changes

Changes that are expected to cause an incompatibility if applicable; deployment changes are likely required

http: Add runtime flag http.max_requests_per_io_cycle for setting the limit on the number of HTTP requests processed from a single connection in a single I/O cycle. Requests over this limit are processed in subsequent I/O cycles. This mitigates CPU starvation by connections that simultaneously send high number of requests by allowing requests from other connections to make progress. This runtime value can be set to 1 in the presence of abusive HTTP/2 or HTTP/3 connections. By default this limit is disabled.
http: Close HTTP/2 and HTTP/3 connections that prematurely reset streams. The runtime key overload.premature_reset_min_stream_lifetime_seconds determines the interval where received stream reset is considered premature (with 1 second default). The runtime key overload.premature_reset_total_stream_count, with the default value of 500, determines the number of requests received from a connection before the check for premature resets is applied. The connection is disconnected if more than 50% of resets are premature. Setting the runtime key envoy.restart_features.send_goaway_for_premature_rst_streams to false completely disables this check.

Changes expected to improve the state of the world and are unlikely to have negative effects

connection limit: fixed a use-after-free bug in the connection limit filter.
docker/publishing: Update base images to resolve various glibc vulnerabilities.
tls: fixed a bug where handshake may fail when both private key provider and cert validation are set.