A heap-buffer-overflow vulnerability is possible in mvfst via a specially crafted message during a QUIC session. This issue affects mvfst versions prior to v2025.07.07.00.
https://www.facebook.com/security/advisories/cve-2025-30403
https://github.com/facebook/mvfst/commit/65b297332191de6e867c4a3139a233fc84c0e7e0