# CVE-2026-46685: RustFS: Reflective CORS with credentials on S3 listener; unauthenticated license metadata endpoint on console

> An attacker can read sensitive data via credentialed cross-origin requests due to permissive CORS settings in RustFS object storage.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 28 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-x5xv-223c-8vm7

## What is CVE-2026-46685?

CVE-2026-46685 is a medium-severity vulnerability in rustfs, published on 28 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

RustFS is a distributed object storage system built in Rust. Prior to 1.0.0-beta.2, when RUSTFS_CORS_ALLOWED_ORIGINS is unset, the RustFS S3 listener's ConditionalCorsLayer reflects any request Origin value back as Access-Control-Allow-Origin and also sets Access-Control-Allow-Credentials: true and Access-Control-Allow-Headers: * on responses, including preflight responses and error responses. This creates a permissive cross-domain policy with untrusted origins. A browser visiting an attacker-controlled page can issue credentialed cross-origin requests to a reachable RustFS deployment and read the response when the victim browser has ambient credentials for the RustFS origin, such as saved HTTP Basic Auth credentials, reverse-proxy SSO cookies, or TLS client certificates. This vulnerability is fixed in 1.0.0-beta.2.

Weakness: CWE-942 (Permissive Cross-domain Security Policy with Untrusted Domains), CWE-346 (Origin Validation Error), CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-46685?


## How do I fix CVE-2026-46685?

No fix has been published for CVE-2026-46685 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-46685 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-46685 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46685 and fix it if it is affected.

What it is: CVE-2026-46685 is a medium-severity vulnerability in rustfs, published on 28 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-46685 exists.

Affected product: rustfs. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-46685/ (Markdown: https://insights.sbomify.com/CVE-2026-46685/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46685
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46685
- OSV: https://osv.dev/vulnerability/CVE-2026-46685

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-46685/
Summaries are generated and may contain mistakes; the official description above is the record.