Issue summary: Remote peer may exhaust heap memory of the QUIC server or client by flooding it with packets containing PATH CHALLENGE frames.

Impact summary: A malicious remote peer can cause an unbounded memory allocation which can lead to an abnormal termination of the application acting as a QUIC client or server and a Denial of Service.

A remote peer may exhaust heap memory by flooding the local QUIC stack with PATH CHALLENGE frames. The local QUIC stack allocates a PATH RESPONSE frame for every PATH CHALLENGE it receives. The allocated PATH RESPONSE frame gets freed only when the remote peer acknowledges reception of the PATH RESPONSE frame which will not be done by a malicious peer.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue. The QUIC stack is outside of OpenSSL FIPS module boundary.