Quicly is an IETF QUIC protocol implementation. Quicly up to commtit d720707 is susceptible to a denial-of-service attack. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using quicly. The vulnerability is addressed with commit 2a95896104901589c495bc41460262e64ffcad5c.
https://github.com/h2o/quicly/security/advisories/GHSA-mp3c-h5gg-mm6p
https://github.com/h2o/quicly/commit/2a95896104901589c495bc41460262e64ffcad5c