GHSA-j972-j939-p2v3

### Impact The loss recovery logic for path probe packets that was added in the v0.50.0 release can be used to trigger a nil-pointer dereference by a malicious QUIC client. In order to do so, the attacker first sends valid QUIC packets from different remote addresses (thereby triggering the newly added path validation logic: the server sends path probe packets), and then sending ACKs for packets received from the server specifically crafted to trigger the nil-pointer dereference. ### Patches v0.50.1 contains a patch that fixes the vulnerability. This release contains a test that generates random sequences of sent packets (both regular and path probe packets), that was used to verify that the patch actually covers all corner cases. ### Workarounds No. ### References This issue has been reported publicly, but without any context, in https://github.com/quic-go/quic-go/issues/4981.