CVE-2026-40937
RustFS missing admin authorization on notification target endpoints, which allows unauthenticated configuration of event webhooks
Record summary
CVE-2026-40937 has a selected CVSS score of 8.3 (high).
Description
RustFS is a distributed object storage system built in Rust. Prior to 1.0.0-alpha.94, all four notification target admin API endpoints in `rustfs/src/admin/handlers/event.rs` use a `check_permissions` helper that validates authentication only (access key + session token), without performing any admin-action authorization via `validate_admin_request`. Every other admin handler in the codebase correctly calls `validate_admin_request` with a specific `AdminAction`. This is the only admin handler file that skips authorization. A non-admin user can overwrite a shared admin-defined notification target by name, causing subsequent bucket events to be delivered to an attacker-controlled endpoint. This enables cross-user event interception and audit evasion. 1.0.0-alpha.94 contains a patch.
Exploitation context
CISA SSVC decision
CISA Coordinator · SSVC 2.0.3 · Evaluated Apr 23, 2026 · Source: CVE List
Affected products and versions
2| Product | Source | Version range | Status |
|---|---|---|---|
rustfsBrowse rustfs / rustfs | CVE List | < 1.0.0-alpha.94 | affected |
| GitHub Advisory | Through 0.0.2 | affected |