# CVE-2026-53656: FiftyOne App server uses wildcard CORS (Access-Control-Allow-Origin: *), enabling cross-origin reads of local server data

> A malicious website can read local FiftyOne server data and files due to wildcard CORS settings, exposing sensitive information to drive-by attackers.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** GHSA-q78p-hj9h-5466, PYSEC-2026-3465

## What is CVE-2026-53656?

CVE-2026-53656 is a medium-severity vulnerability in voxel51 fiftyone, published on 21 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

FiftyOne is an open-source platform for refining high-quality datasets and visual AI models. Prior to 1.17.0, the FiftyOne App/API server in fiftyone/server/app.py and the /media route in fiftyone/server/routes/media.py unconditionally return Access-Control-Allow-Origin: *. Because the embedded server is local and unauthenticated, a malicious website visited by the user can read cross-origin responses. The /media endpoint accepts a filesystem path, allowing a drive-by page to read files accessible to the server process and exfiltrate them without additional clicks. The allowed_origins configuration and FIFTYONE_ALLOWED_ORIGINS environment variable now make cross-origin access explicit, while the default policy is same-origin. This issue is fixed in version 1.17.0.

Weakness: CWE-942 (Permissive Cross-domain Security Policy with Untrusted Domains), CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2026-53656?

3 open source packages ship an affected version, including fiftyone.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fiftyone` | PyPI | All versions | 1.17.0 |
| `fiftyone` | PyPI | All versions | 1.17.0 |
| `fiftyone` | PyPI | All versions | 1.17.0 |

## How do I fix CVE-2026-53656?

Upgrade fiftyone to 1.17.0 or later.

## Is CVE-2026-53656 being exploited?

There is no known exploitation of CVE-2026-53656 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53656 and fix it if it is affected.

What it is: CVE-2026-53656 is a medium-severity vulnerability in voxel51 fiftyone, published on 21 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-53656 in the wild and no public exploit code.

Affected packages and fixed versions:
- fiftyone (PyPI): affected all versions; fixed in 1.17.0
- fiftyone (PyPI): affected all versions; fixed in 1.17.0
- fiftyone (PyPI): affected all versions; fixed in 1.17.0

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-2026-53656/ (Markdown: https://insights.sbomify.com/CVE-2026-53656/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53656
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53656
- OSV: https://osv.dev/vulnerability/CVE-2026-53656

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53656/
Summaries are generated and may contain mistakes; the official description above is the record.