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.
- 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
- None listed
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.
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.
Sources
Also known as GHSA-x5xv-223c-8vm7.