CVE-2026-94383: MISP Blocklist Workflow Module: Arbitrary Script Execution via Unrestricted File Extension
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
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Enforce a strict whitelist of allowed file extensions (txt, list, blocklist, csv) on the user-supplied blocklist filename parameter before the file is processed.
MISP Blocklist Workflow Module blocklist filename extension allowlist = txt, list, blocklist, csv - Compensating control
Limit access to the MISP blocklist workflow module to site-administrator accounts only (the module is restricted to that role).
Event History
Frequently Asked Questions
Who can exploit this issue?
Exploitation requires site-administrator privileges in MISP because the blocklist workflow module is restricted to that role. No additional user interaction is required after the administrator triggers the workflow with a crafted filename.
Are all affected MISP deployments exposed to code execution?
Code execution depends on the underlying web server being configured to interpret and execute scripts from the MISP export directory. If scripts are not executable from that directory, the described arbitrary script execution path does not apply.
What is the impact if exploitation succeeds?
An attacker can execute arbitrary code with the privileges of the web server process. This can compromise the confidentiality, integrity, and availability of the MISP server.
Which versions are affected?
Versions earlier than 2.5.47 are affected.