What’s Vulnerable › Vulnerabilities

CVE-2026-25480: FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-09 · updated 2026-06-17
• Weakness: CWE-176

Description

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.

Affected products

• litestar-org litestar: before 2.20.0 — fixed in 2.20.0

How to fix

Upgrade to a fixed version: litestar-org litestar 2.20.0. Check the vendor advisory for mitigations.

References

• https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0
• https://github.com/litestar-org/litestar/commit/85db6183a76f8a6b3fd6ee3c88d860b9f37a2cca
• https://github.com/litestar-org/litestar/releases/tag/v2.20.0
• https://github.com/litestar-org/litestar/security/advisories/GHSA-vxqx-rh46-q2pg

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