CVE-2026-40937 RustFS: Missing admin authorization on notification target endpoints allows unauthenticated configuration of event webhooks
Unauthenticated users can configure event webhooks due to missing admin authorization, enabling cross-user event interception and audit evasion.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-40937?
CVE-2026-40937 is a high-severity missing authorization vulnerability in rustfs, published on 22 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-862
Which versions are affected by CVE-2026-40937?
2 open source packages ship an affected version, including rustfs. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
rustfs crates.io | All versions to 0.0.2 | None |
rustfs crates.io | All versions to 0.0.2 | None |
Products include Rustfs Rustfs.
How do I fix CVE-2026-40937?
No fix has been published for CVE-2026-40937 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-40937 being exploited?
There is no known exploitation of CVE-2026-40937 in the wild and no public exploit code.
Other vulnerabilities in rustfs
- CVE-2025-68926 RustFS has a gRPC Hardcoded Token Authentication Bypass
- CVE-2026-27822 Rust has Critical Stored XSS in Preview Modal, leading to Administrative Account Takeover
- CVE-2025-68705 RustFS Path Traversal Vulnerability
- CVE-2026-27607 RustFS's Missing Post Policy Validation leads to Arbitrary Object Write
- CVE-2026-21862 RustFS sourceIp bypass via spoofed X-Forwarded-For/Real-IP headers
Sources
Also known as GHSA-pfcq-4gjr-6gjm.