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CVE-2026-56423 is a critical broken access control vulnerability in MISP Core affecting the bulk deletion flows for Event Reports and Sharing Groups. The flaw is in the deleteSelection handlers, which authorized deletion based on broad role-level permissions instead of validating authorization for each selected object. In EventReportsController::deleteSelection, deletion was gated by the global perm_add capability rather than a per-report delete authorization check, allowing a contributor-level user to submit identifiers for reports owned by other organisations and hard-delete them across the instance. In SharingGroupsController::deleteSelection, deletion was gated by the global perm_sharing_group capability rather than verifying ownership of each selected sharing group, allowing deletion of sharing groups owned by other organisations. The issue arises from missing per-object authorization enforcement in bulk operations, unlike the stricter checks used in corresponding single-object deletion paths.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository is a real proof-of-concept exploit for CVE-2026-56423, a broken access control vulnerability in MISP bulk deletion flows. The main exploit is exploit.py, a standalone Python script that targets authenticated MISP API endpoints over HTTPS. It demonstrates that a low-privileged contributor with perm_add can delete another organisation's Event Report by calling /eventReports/deleteSelection, even though the normal /eventReports/delete/{id} endpoint correctly denies the same action. The exploit uses API auth keys, disables TLS certificate validation, verifies the victim report exists, performs a denied control request, triggers the vulnerable bulk-delete request, and confirms the report was hard-deleted. Repository structure is small and focused: exploit.py contains the PoC; README.md documents the vulnerability, affected/fixed versions, usage, and impact; ANALYSIS.md provides code-level root cause analysis of the vulnerable MISP controllers and the 2.5.42 fix; EVIDENCE.txt records observed vulnerable vs patched behavior; lab/setup.sh and lab/teardown.sh automate a local Docker-based reproduction environment using misp-docker. The lab script provisions a second organisation, a contributor user, enables MISP.enable_themes, creates a victim event/report, and outputs credentials for running the exploit. Primary capability: unauthorized hard deletion of foreign Event Reports across organisations on MISP <= 2.5.41 when MISP.enable_themes is enabled. Documentation also states the same flawed authorization pattern affects SharingGroupsController::deleteSelection, though the included exploit code only exercises Event Reports. This is an authenticated web/network attack against MISP's API, not merely a detector, and the PoC is operational but basic rather than framework-integrated.
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A specific vulnerability fixed in MISP 2.5.42 as part of a security hardening release. The content lists the identifier but does not describe the flaw type.
A critical broken access control vulnerability in MISP Core bulk deletion handlers that allows an authenticated user with broad role permissions to delete Event Reports or Sharing Groups belonging to other organisations due to missing per-object authorization checks.
A specific vulnerability fixed in MISP 2.5.42 as part of a security hardening release; the content lists the CVE but does not describe its technical details.
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