The MISP blocklist workflow module accepted a user-supplied blocklist filename parameter without validating the file extension. The only sanitization applied was basename() to strip path components and a check for empty or dot values. A site administrator could specify a filename with an arbitrary extension that would be placed in the MISP export directory. If the underlying web server is configured to interpret and execute scripts from that directory, the resulting file could be invoked, leading to arbitrary code execution in the context of the web server process.

The vulnerability requires the attacker to hold site-administrator privileges within MISP, as the blocklist workflow module is restricted to that role. No additional user interaction is required beyond triggering the workflow action with a crafted filename parameter. The impact is full compromise of the MISP server's confidentiality, integrity, and availability, as arbitrary script execution grants the attacker the same privileges as the web server user.

Version affected: <2.5.47

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Advisories

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Fixes

Solution

The vulnerability is remediated by enforcing a strict whitelist of allowed file extensions (txt, list, blocklist, csv) on the blocklist filename parameter before the file is processed. Any filename with an extension outside this whitelist is rejected with an error, preventing an attacker from placing files with executable or dangerous extensions (e.g., .php, .phtml) into the MISP export directory where they could be interpreted by the web server.


Workaround

No workaround given by the vendor.

History

Mon, 21 Sep 2026 13:00:00 +0000

Type Values Removed Values Added
Description The MISP blocklist workflow module accepted a user-supplied blocklist filename parameter without validating the file extension. The only sanitization applied was basename() to strip path components and a check for empty or dot values. A site administrator could specify a filename with an arbitrary extension that would be placed in the MISP export directory. If the underlying web server is configured to interpret and execute scripts from that directory, the resulting file could be invoked, leading to arbitrary code execution in the context of the web server process. The vulnerability requires the attacker to hold site-administrator privileges within MISP, as the blocklist workflow module is restricted to that role. No additional user interaction is required beyond triggering the workflow action with a crafted filename parameter. The impact is full compromise of the MISP server's confidentiality, integrity, and availability, as arbitrary script execution grants the attacker the same privileges as the web server user. Version affected: <2.5.47
Title MISP Blocklist Workflow Module: Arbitrary Script Execution via Unrestricted File Extension
Weaknesses CWE-20
CWE-434
References
Metrics cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: CIRCL

Published:

Updated: 2026-09-21T12:52:03.355Z

Reserved: 2026-09-21T12:52:01.101Z

Link: CVE-2026-94383

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-09-21T13:17:13.560

Modified: 2026-09-21T13:17:13.667

Link: CVE-2026-94383

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses