CVE-2026-86451: misp Auth Bypass — Fix

Description

Affected versions of MISP allow authenticated users to retrieve object-reference records by UUID through EventGraphTool::get_reference_data() without first checking whether the requester is authorized to view the object the reference belongs to. The vulnerable code queried ObjectReference.uuid directly and returned the matching row whenever it existed. Because no parent-object ACL was applied, a user who knew or obtained a reference UUID could retrieve information associated with an object outside their normal access scope. The commit explicitly states that any object reference could be returned by UUID without authorizing its parent object. The fix retrieves the referenced object's object_id and calls fetchObjectSimple() with the current user. If the user cannot access that parent object, MISP now returns NotFoundException instead of exposing the reference. Version affected: ≤2.5.45

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0017

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-639 CWE-639

CWE-862 Missing Authorization

Affected Products

Vendor	Product	Versions
misp-project	misp	< 2.5.45

References

Advisories & Patches

https://github.com/MISP/MISP/commit/c0cb5c9f8

Frequently Asked Questions

What is CVE-2026-86451? +

Affected versions of MISP allow authenticated users to retrieve object-reference records by UUID through EventGraphTool::get_reference_data() without first checking whether the requester is authorized to view the object the reference belongs to. The vulnerable code queried ObjectReference.uuid directly and returned the matching row whenever it existed. Because no parent-object ACL was applied, a user who knew or obtained a reference UUID could retrieve information associated with an object outside their normal access scope. The commit explicitly states that any object reference could be returned by UUID without authorizing its parent object. The fix retrieves the referenced object's object_id and calls fetchObjectSimple() with the current user. If the user cannot access that parent object, MISP now returns NotFoundException instead of exposing the reference. Version affected: ≤2.5.45 It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-86451? +

CVE-2026-86451 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0017, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-86451? +

CVE-2026-86451 affects products from misp-project, specifically: misp. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-86451? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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