CVE intelligence and bounded remediation
CVE-2020-5239 — Mailu Mailu security vulnerability
In Mailu before version 1.7, an authenticated user can exploit a vulnerability in Mailu fetchmail script and gain full access to a Mailu instance. Mailu servers that have open registration or untrusted users are most impacted. The master and 1.7 branches are patched on our git repository. All Docker images published on docker.io/mailu for tags 1.5, 1.6, 1.7 and master are patched. For detailed instructions about patching and securing the server afterwards, see https://github.com/Mailu/Mailu/issues/1354
- Severity
- High
- CVSS
- 8.8 (3.1)
- Published
- 2020-02-13
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-863
Affected products
- mailu / mailu
Matched remediation archetype
Authorization bypass, IDOR, and cross-tenant access
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
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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