GHSA-c33x-xqrf-c478

An attacker can cause its peer to run out of memory by sending a large number of NEWCONNECTIONID frames that retire old connection IDs. The receiver is supposed to respond to each retirement frame with a RETIRECONNECTIONID frame. The attacker can prevent the receiver from sending out (the vast majority of) these RETIRECONNECTIONID frames by collapsing the peers congestion window (by selectively acknowledging received packets) and by manipulating the peer's RTT estimate.

I published a more detailed description of the attack and its mitigation in this blog post: https://seemann.io/posts/2024-03-19-exploiting-quics-connection-id-management/. I also presented this attack in the IETF QUIC working group session at IETF 119: https://youtu.be/JqXtYcZAtIA?si=nJ31QKLBSTRXY35U&t=3683

There's no way to mitigate this attack, please update quic-go to a version that contains the fix.