EUVD-2026-32999CVSS VectorNVD
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
3DescriptionNVD
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.
AnalysisAI
CORS origin reflection in RustFS's S3 listener exposes stored object data to cross-origin theft via browser-credentialed requests against all versions prior to 1.0.0-beta.2. When the RUSTFS_CORS_ALLOWED_ORIGINS environment variable is unset - the default state - the ConditionalCorsLayer middleware reflects any incoming Origin header verbatim as Access-Control-Allow-Origin while simultaneously asserting Access-Control-Allow-Credentials: true and Access-Control-Allow-Headers: *, including on preflight and error responses, nullifying the browser's same-origin policy protections. …
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