CVE intelligence and bounded remediation
CVE-2026-40874 — mailcow: dockerized is an open source groupware/email suite based on docker
mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, no administrator verification takes place when deleting Forwarding Hosts with `/api/v1/delete/fwdhost`. Any authenticated user can call this API. Checks are only applied for edit/add actions, but deletion can still significantly disrupt the mail service. Version 2026-03b fixes the vulnerability.
- Severity
- Medium
- CVSS
- 6 (4.0)
- Published
- 2026-04-21
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-284
Affected products
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Matched remediation archetype
Authorization bypass, IDOR, and cross-tenant access
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Check exposure
- Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
- Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
- Use synthetic fixtures to compare intended access matrices without accessing another user's real data.
Remediate safely
- Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
- Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
- Add deny-by-default policy tests for horizontal and vertical access across every affected transport.
Authoritative sources
Complete CVE record and remediation plan
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