CVE-2026-25480CWE-176

FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)

Medium · published February 9, 2026

CVSS v3.1
6.5
EPSS
1%
Percentile
46.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00566 · 46.2th percentile
Weakness
CWE-176 · Improper Handling of Unicode Encoding
Published
2026-02-09T18:49Z
EPSS history
Timeline
  • 09 FEB 18:49Z
    FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)
    cvelistv5