Impact

Cloudflare quiche was discovered to be vulnerable to an infinite loop when sending packets containing RETIRECONNECTIONID frames.

QUIC connections possess a set of connection identifiers (IDs); see Section 5.1 of RFC 9000. Once the QUIC handshake completes, a local endpoint is responsible for issuing and retiring Connection IDs that are used by the remote peer to populate the Destination Connection ID field in packets sent from remote to local. Each Connection ID has a sequence number to ensure synchronization between peers

An unauthenticated remote attacker can exploit this vulnerability by first completing a handshake and then sending a specially-crafted set of frames that trigger a connection ID retirement in the victim. When the victim attempts to send a packet containing RETIRECONNECTIONID frames, Section 19.16 of RFC 9000 requires that the sequence number of the retired connection ID must not be the same as the sequence number of the connection ID used by the packet. In other words, a packet cannot contain a frame that retires itself. In scenarios such as path migration, it is possible for there to be multiple active paths with different active connection IDs that could be used to retire each other. The exploit triggered an unintentional behaviour of a quiche design feature that supports retirement across paths while maintaining full connection ID synchronization, leading to an infinite loop.

Patches

quiche 0.24.5 is the earliest version containing the fix for the issue

Summary

Cloudflare quiche was discovered to be vulnerable to memory resource exhaustion due to unbounded queuing of post-handshake client migration events.

Impact

quiche supports the connection migration features described in Section 9 of RFC 9000, which allows a single QUIC connection to survive changes in the network path. Although quiche implements the protections described in Section 9.3 of RFC 9000 to limit server state commitment, it was discovered that the collection of PathEvents, intended to be consumed by applications via the patheventnext() function, was not bounded.

Once the QUIC handshake completed, a peer could exploit rapid source address migration in order to cause unbounded queuing of the PathEvent::ReusedSourceConnectionId type. Servers are vulnerable even if active connection migration is disabled.

Mitigation:

Applications can call patheventnext() to drain the PathEvent collection, mitigating the attack.

Users are requested to upgrade to quiche 0.29.3 which is the earliest version that prevents excessive queueing of PathEvent::ReusedSourceConnectionId.

Summary

Cloudflare quiche's HTTP/3 layer was discovered to be vulnerable to resource exhaustion (i.e., memory) by means of specially crafted HTTP/3 frames.

Impact

HTTP/3 defines multiple frame types to support HTTP message exchanges and connection management. Each frame has a length and a payload whose length depends on the frame type. quiche was found to be vulnerable when parsing some frame types to pre-allocating memory based on the declared length. An attacker would not need to send the number of declared bytes to trigger this issue.

In addition, quiche was found to not apply QPACK decompression limits correctly. This could allow an attacker to send specially crafted HEADERS frames that would cause more memory commitment than otherwise advertised by MAXFIELDSECTIONSIZE (configured by setmaxfieldsectionsize()).

Mitigation:

Users are requested to upgrade to quiche 0.29.3 which is the earliest version containing the fix for this issue.

Credits: Disclosed responsibly by Sébastien Féry

Impact

Cloudflare Quiche was affected by 2 use-after-free vulnerabilities in the connection ID iterator FFI functions.

The quicheconnectioniditernext and quicheconnretiredscidnext functions would return a pointer to a ConnectionId to the applications via function arguments, but the the owned ConnectionId would be dropped at the end of those functions' scope.

Only applications using those FFI functions are affected. The FFI API is disabled by default by a build-time feature flag.

quiche 0.29.2 is the earliest version containing the fix for this issue.

Impact quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption.

QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATHCHALLENGE frame responds by sending a PATHRESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATHCHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATHRESPONSE frames can only be sent at the slower rate than they are received, leading to storage of path validation data in an unbounded queue.

Patches Quiche versions greater than 0.19.0 address this problem.

References CVE-2023-6193 RFC 9000 Section 8.2