CVE intelligence and bounded remediation

CVE-2026-54398 — An authorization flaw in MISP’s object add/edit handling allowed an authenticated user with object editing permissions to assign a MISP...

Medium CVSS 5.3

An authorization flaw in MISP’s object add/edit handling allowed an authenticated user with object editing permissions to assign a MISP object, or attributes contained within an object, to a sharing group that the user was not authorized to use or view. When editing objects, the sharing group validation was performed against the wrong request data structure after object fields had been merged to the top level, causing the check to be bypassed. In addition, attributes embedded in objects were not individually validated for authorized sharing group use. An attacker could craft a request with distribution set to 4 and an arbitrary sharing_group_id, potentially disclosing the existence or name of otherwise non-visible sharing groups and improperly modifying the distribution metadata of objects or contained attributes.

Severity
Medium
CVSS
5.3 (4.0)
Published
2026-06-12
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-863

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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