CVE-2026-46685CWE-306CWE-346CWE-942

RustFS: Reflective CORS with credentials on S3 listener; unauthenticated license metadata endpoint on console

Medium · published May 28, 2026

CVSS v4.0
6.0
EPSS
0%
Percentile
3.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.0 · MEDIUM
Vector
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
EPSS
0.00148 · 3.6th percentile
Weaknesses
CWE-306 · Missing Authentication for Critical Function; CWE-346 · Origin Validation Error; CWE-942 · Permissive Cross-domain Security Policy with Untrusted Domains
Published
2026-05-28T18:41Z
EPSS history
Timeline
  • 28 MAY 18:41Z
    RustFS: Reflective CORS with credentials on S3 listener; unauthenticated license metadata endpoint on console
    cvelistv5