Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, FileStore maps cache keys to filenames using Unicode NFKD normalization and ord() substitution without separators, creating key collisions. When FileStore is used as response-cache backend, an unauthenticated remote attacker can trigger cache key collisions via crafted paths, causing one URL to serve cached responses of another (cache poisoning/mixup). This vulnerability is fixed in 2.20.0.
https://github.com/litestar-org/litestar/security/advisories/GHSA-vxqx-rh46-q2pg
https://github.com/litestar-org/litestar/releases/tag/v2.20.0
https://github.com/litestar-org/litestar/commit/85db6183a76f8a6b3fd6ee3c88d860b9f37a2cca
https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0