Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, in litestar.middleware.allowed_hosts, allowlist entries are compiled into regex patterns in a way that allows regex metacharacters to retain special meaning (e.g., . matches any character). This enables a bypass where an attacker supplies a host that matches the regex but is not the intended literal hostname. This vulnerability is fixed in 2.20.0.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:LI:LA:N6.5/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NOther