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Fencer Intel
critical 9.4

CVE-2026-56422 json

MISP Core: Mass Assignment and Object Re-ownership via Unvalidated Request Fields

published 4mo ago modified 4mo ago also EUVD-2026-38225

cvss
9.4
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

Multiple MISP core controllers and model capture paths accepted client-controlled request fields such as primary keys (id) and ownership/scope foreign keys (event_id, org_id, user_id, sharing_group_id, galaxy_cluster_uuid, organisation_uuid, and related nested object identifiers) without consistently stripping, pinning, or revalidating them against the server-authorized object.

In affected paths, an authenticated user with access to one authorized object could submit crafted REST or form payloads that caused MISP to save data against a different object than the one checked by the authorization logic. Depending on the endpoint, this could allow object overwrite, object re-parenting, ownership transfer, unauthorized sharing-group scoping, event/object injection, proposal retargeting, or stored attacker-controlled content appearing in another user’s context.

The fixes harden affected create/edit/import flows by stripping client-supplied primary keys on create-only saves, re-pinning route- or database-authorized identifiers before save operations, validating effective sharing-group scope, and adding field whitelists where ownership fields must never be editable. The initial broad fix also added a central CRUDComponent::edit() primary-key re-pin so payload-supplied IDs cannot redirect saves away from the already-authorized row. GitHub’s patch for 7acf8220c describes this central issue as CRUDComponent::edit() copying supplied fields, including a payload primary key, onto the loaded record, allowing CakePHP save() to update an arbitrary row unless the loaded ID is re-pinned.

Patch / fix

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4mo ago

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA 4.0 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • misp misp

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.