GHSA-4v7x-pqxf-cx7m net/http, x/net/http2: close connections when receiving too many headers

• Go net/http: < 1.21.9 → fixed in 1.21.9 • Go golang.org/x/net/http2: < 0.23.0 → fixed in 0.23.0 • Go net/http: >= 1.22.0-0, < 1.22.2 → fixed in 1.22.2 • Go golang.org/x/net: < 0.23.0 → fixed in 0.23.0

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames. Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed. This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send. The fix sets a limit on the amount of excess header frames we will process before closing a connection.