CVE-2026-40937 json
RustFS missing admin authorization on notification target endpoints, which allows unauthenticated configuration of event webhooks
published 2026-04-22 6 mo ago modified 2026-06-17 4 mo ago also GHSA-pfcq-4gjr-6gjm , EUVD-2026-25092
- cvss
- 8.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 22%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 6 mo ago
Exploit prediction
0.29% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L |
| GitHub | 3.1 | 8.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | rustfs | <=0.0.2 |
no fix listed |
Affected products
- rustfs rustfs
Classification
- Weakness
-
- CWE-862 Missing Authorization
References
-
github.com
/rustfs/rustfs/security/advisories/GHSA-pfcq-4gjr-6gjm
web, mitigation, vendor-advisory
-
github.com
/rustfs/rustfs/releases/tag/1.0.0-alpha.94
web, product, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-40937
advisory
-
github.com
/rustfs/rustfs
package
Sources
- CVE List CVE-2026-40937
- GitHub Advisory GHSA-pfcq-4gjr-6gjm
- NVD CVE-2026-40937
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