dbcve.org
RustfsApplication

CVE-2026-40937

HIGH · 8.3 CVSS v3.1 Published 2026-04-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
89/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Four notification target admin API endpoints in RustFS use a `check_permissions` helper that validates only authentication (access key + session token) but skips admin-action authorization via `validate_admin_request`. This allows any authenticated non-admin user to overwrite shared admin-defined notification targets by name, causing bucket events to be redirected to attacker-controlled endpoints for cross-user event interception and audit evasion.

MitigationUpgrade to RustFS 1.0.0-alpha.94 which adds the missing `validate_admin_request` authorization checks to all four notification target endpoints.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RustfsApplication
Affected:= 1.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify RustFS version
    Check the installed RustFS version using the CLI command 'rustfs --version' or inspect the binary/package metadata
    Affected if Version is 1.0.0 and less than 1.0.0-alpha.94 (or if the version string contains 'alpha' and the number is below 94)
  2. Verify notification target admin endpoints exist
    Inspect the event.rs source file or binary for the four notification target admin API handlers (typically endpoints under /admin/notifications or similar admin notification target paths)
    Affected if The notification target admin endpoints are present and accessible in the API
  3. Check for missing authorization validation
    Review the source code of event.rs for the four notification target handlers: verify they only call check_permissions but do NOT call validate_admin_request
    Affected if The handlers call check_permissions but lack validate_admin_request validation (only authentication, no authorization)
  4. Test endpoint access as non-admin user
    Using valid credentials for a non-admin authenticated user, attempt PUT/POST requests to the notification target admin endpoints (e.g., /api/v1/admin/notification-targets)
    Affected if A non-admin authenticated user can successfully modify or create notification targets (should require admin role)

If running RustFS version 1.0.0 prior to alpha.94 and the notification target admin endpoints accept requests from authenticated non-admin users (missing validate_admin_request), the environment is vulnerable to this authorization bypass.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to RustFS 1.0.0-alpha.94 which adds the missing `validate_admin_request` authorization checks to all four notification target endpoints.

Recommended fix High confidence

1.0.0-alpha.94

  1. Identify the current Rustfs version in use
  2. Upgrade Rustfs to version 1.0.0-alpha.94 or later
  3. Verify the upgrade by checking that the event handlers in rustfs/src/admin/handlers/event.rs now call validate_admin_request

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Rustfs Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,040
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40937 in production — separate from our analysis above.

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