CVE-2026-103659: MISP authorization bypass in event flattening
CVE-2026-103659 · Severity: info · Published 2026-10-01
MISP is a threat intelligence platform that organizations use to share and manage indicators of compromise and attack patterns. The event flattening feature, which simplifies event structure for export or display, fails to re-apply access controls when converting restricted object-level data to event-level attributes. An authenticated user with access to a community-shared event can retrieve sensitive threat intelligence from organization-restricted or sharing-group-restricted objects within that event, even though they should not have access to those objects.</brief>
<parameter name="technical_details">An authorization bypass occurs in the event flattening feature when object containment is removed from a query. The application fails to re-apply object-level distribution and sharing-group access control checks to attributes promoted to top-level status, allowing a community-distribution event viewer to access attributes from restricted objects. The vulnerability requires an authenticated user and a community-distributed event containing at least one object with stricter distribution controls (organization-only or sharing-group-limited).</technical_details>
<parameter name="severity">medium
No. Junglewise Threat Intelligence has no report of CVE-2026-103659 being exploited in the wild.
How severe is CVE-2026-103659?
Informational severity, published 1 October 2026.
Which products and versions are affected?
MISP Project MISP before 2.5.48.
Is there a fix for CVE-2026-103659?
Yes: fixed in 2.5.48. Until then: Restrict the use of the event flattening feature to trusted users, or disable it if not required for operational workflows, until an upgrade to a patched version is possible. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-103659 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-103659?
Check whether you run MISP Project MISP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
Fixed in: 2.5.48
Restrict the use of the event flattening feature to trusted users, or disable it if not required for operational workflows, until an upgrade to a patched version is possible.