Unbounded queuing of path validation messages in cloudflare-quiche

Medium5.3CVE-2023-6193 · Published Dec 12, 2023

### 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](https://datatracker.ietf.org/doc/html/rfc9000#section-8.2)) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE 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](https://www.cve.org/CVERecord?id=CVE-2023-6193) [RFC 9000 Section 8.2](https://datatracker.ietf.org/doc/html/rfc9000#section-8.2)