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Fencer Intel
medium 5.3

CVE-2026-54398 json

MISP object edit authorization bypass allows unauthorized sharing group assignment

published 4mo ago modified 3mo ago also EUVD-2026-36603

cvss
5.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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.

Patch / fix

  • misp misp 2.5.40

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/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

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.