quic-go is an implementation of the QUIC protocol in Go. An off-path attacker can inject an ICMP Packet Too Large packet. Since affected quic-go versions used IP_PMTUDISC_DO, the kernel would then return a "message too large" error on sendmsg, i.e. when quic-go attempts to send a packet that exceeds the MTU claimed in that ICMP packet. By setting this value to smaller than 1200 bytes (the minimum MTU for QUIC), the attacker can disrupt a QUIC connection. Crucially, this can be done after completion of the handshake, thereby circumventing any TCP fallback that might be implemented on the application layer (for example, many browsers fall back to HTTP over TCP if they're unable to establish a QUIC connection). The attacker needs to at least know the client's IP and port tuple to mount an attack. This vulnerability is fixed in 0.48.2.

quic-go is an implementation of the QUIC protocol in Go. Prior to version 0.42.0, an attacker can cause its peer to run out of memory sending a large number of `NEW_CONNECTION_ID` frames that retire old connection IDs. The receiver is supposed to respond to each retirement frame with a `RETIRE_CONNECTION_ID` frame. The attacker can prevent the receiver from sending out (the vast majority of) these `RETIRE_CONNECTION_ID` frames by collapsing the peers congestion window (by selectively acknowledging received packets) and by manipulating the peer's RTT estimate. Version 0.42.0 contains a patch for the issue. No known workarounds are available.

quic-go is an implementation of the QUIC protocol (RFC 9000, RFC 9001, RFC 9002) in Go. An attacker can cause its peer to run out of memory sending a large number of PATH_CHALLENGE frames. The receiver is supposed to respond to each PATH_CHALLENGE frame with a PATH_RESPONSE frame. The attacker can prevent the receiver from sending out (the vast majority of) these PATH_RESPONSE frames by collapsing the peers congestion window (by selectively acknowledging received packets) and by manipulating the peer's RTT estimate. This vulnerability has been patched in versions 0.37.7, 0.38.2 and 0.39.4.

quic-go is an implementation of the QUIC protocol in Go. Starting in version 0.37.0 and prior to version 0.37.3, by serializing an ACK frame after the CRYTPO that allows a node to complete the handshake, a remote node could trigger a nil pointer dereference (leading to a panic) when the node attempted to drop the Handshake packet number space. An attacker can bring down a quic-go node with very minimal effort. Completing the QUIC handshake only requires sending and receiving a few packets. Version 0.37.3 contains a patch. Versions before 0.37.0 are not affected.

quic-go through 0.27.0 allows remote attackers to cause a denial of service (CPU consumption) via a Slowloris variant in which incomplete QUIC or HTTP/3 requests are sent. This occurs because mtu_discoverer.go misparses the MTU Discovery service and consequently overflows the probe timer. NOTE: the vendor's position is that this behavior should not be listed as a vulnerability on the CVE List