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

> Attackers can poison the response cache in Litestar by exploiting key collisions, causing users to receive incorrect cached data.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Feb 2026
- **Updated:** 10 Feb 2026
- **Also known as:** GHSA-vxqx-rh46-q2pg, PYSEC-2026-2197

## What is CVE-2026-25480?

CVE-2026-25480 is a medium-severity vulnerability in litestar-org litestar, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-176 (Improper Handling of Unicode Encoding)

## Which versions are affected by CVE-2026-25480?

3 open source packages ship an affected version, including litestar. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `litestar` | PyPI | All versions | 2.20.0 |
| `litestar` | PyPI | From 2.19.0 | 2.20.0 |
| `litestar` | PyPI | From 2.19.0 | 2.20.0 |

Products: Litestar Litestar.

## How do I fix CVE-2026-25480?

Upgrade litestar to 2.20.0 or later.

## Is CVE-2026-25480 being exploited?

There is no known exploitation of CVE-2026-25480 in the wild and no public exploit code.

## Other vulnerabilities in litestar-org litestar

- [CVE-2024-52581](https://insights.sbomify.com/CVE-2024-52581/): Litestar allows unbounded resource consumption (DoS vulnerability) (high 8.2)
- [CVE-2026-25478](https://insights.sbomify.com/CVE-2026-25478/): Litestar has a CORS origin allowlist bypass due to unescaped regex metacharacters in allowed origins (high 7.4)
- [CVE-2026-25479](https://insights.sbomify.com/CVE-2026-25479/): Litestar has an AllowedHosts validation bypass due to unescaped regex metacharacters in configured host patterns (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25480 and fix it if it is affected.

What it is: CVE-2026-25480 is a medium-severity vulnerability in litestar-org litestar, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-25480 in the wild and no public exploit code.

Affected packages and fixed versions:
- litestar (PyPI): affected all versions; fixed in 2.20.0
- litestar (PyPI): affected from 2.19.0; fixed in 2.20.0
- litestar (PyPI): affected from 2.19.0; fixed in 2.20.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-25480/ (Markdown: https://insights.sbomify.com/CVE-2026-25480/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25480
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25480
- OSV: https://osv.dev/vulnerability/CVE-2026-25480

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25480/
Summaries are generated and may contain mistakes; the official description above is the record.