CVE-2026-40937 json
RustFS missing admin authorization on notification target endpoints, which allows unauthenticated configuration of event webhooks
published 6mo ago modified 4mo ago also EUVD-2026-25092 , GHSA-pfcq-4gjr-6gjm
- 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
Is CVE-2026-40937 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 6mo ago
Exploit prediction
0.29% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-09).
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
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.