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
"}],"value":"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.\n\nThe 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.\n\nVersion affected: <2.5.47"}],"impacts":[{"capecId":"CAPEC-170","descriptions":[{"lang":"en","value":"CAPEC-170 File Upload"}]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.6,"baseSeverity":"HIGH","privilegesRequired":"HIGH","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-434","description":"CWE-434 Unrestricted Upload of File with Dangerous Type","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-20","description":"CWE-20 Improper Input Validation","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-21T12:52:03.355Z","orgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","shortName":"CIRCL"},"references":[{"name":"Security patch","tags":["patch"],"url":"https://github.com/MISP/MISP/commit/e5a943178"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"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.
"}],"value":"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."}],"title":"MISP Blocklist Workflow Module: Arbitrary Script Execution via Unrestricted File Extension","x_gcve":[{"extensions":{"bcp-05-x-01":{"ai_annotations":[{"ai_level":"generated","description":"Draft vulnerability metadata was generated from a git-format patch using an Ollama-hosted language model. Human validation is required before publication.","gna_source":1,"models":[{"gna_source":1,"identifier":"qwen3.8:27b","name":"qwen3.8:27b","source":"ollama"}],"review_status":"review","scope":"record","tags":["ai-computer-assisted:llm-generated","ai-computer-assisted:classification"]}]},"bcp-05-x-02":{"x_patch2vuln":{"assumptions":["The commit message states 'site admin only', which is taken as evidence that the vulnerable workflow module requires MISP site-administrator privileges. The exact privilege model and whether lower-privilege roles could reach this code path is not confirmed by the patch alone.","The assumption that the MISP export directory is web-accessible and that the web server is configured to execute scripts (e.g., PHP) from that directory is inferred from the commit subject 'arbitrary script execution'. The patch does not include web server configuration evidence.","The affected version boundary (prior to v2.5.47) is inferred from the tag_version_boundary metadata showing v2.5.47 as the nearest tag with 142 commits after the fix. The exact first affected version is not stated in the patch.","CAPEC-170 (File Upload) is the closest available attack pattern, but the actual mechanism is a workflow parameter specifying a filename rather than a traditional file upload. This mapping is approximate.","The CVSS PR:H rating assumes that 'site admin' in MISP corresponds to a high-privilege role requiring authentication and elevated permissions, consistent with MISP's role model."],"capecRationale":[{"capecId":"CAPEC-170","rationale":"CAPEC-170 describes an attacker uploading or placing a file with a dangerous extension into a target directory where it can be executed. In this case, a site admin specifies a blocklist filename with a dangerous extension (e.g., .php) that is placed in the MISP export directory. The mechanism is not a traditional multipart upload but rather a workflow parameter that results in a file being written to a web-accessible location. CAPEC-170 is the closest available pattern; the uncertainty is that the file is not uploaded via a standard upload endpoint but is instead referenced by name in a workflow action, making the mapping approximate."}],"commit":"e5a9431784b4a78faddc0cc6efc2a287f2fd3d08","confidence":"medium","credits":[{"lang":"en","type":"reporter","value":"Jeroen Pinoy"},{"lang":"en","type":"remediation developer","value":"iglocska"}],"cvssRationale":"AV:N: MISP is a network-accessible web application. AC:L: The attack requires only specifying a filename with a dangerous extension in a workflow parameter; no race conditions or complex timing are needed. AT:N: No manipulation of the target system is required beyond the normal API call. PR:H: The commit message explicitly states 'site admin only', requiring high-privilege MISP access. UI:N: No victim interaction is needed; the workflow action is triggered by the admin themselves. VC:H, VI:H, VA:H: Arbitrary script execution on the MISP server compromises all three local security properties. SC:N, SI:N, SA:N: The impact is confined to the MISP server; no evidence of lateral impact on other systems is present in the patch.","fixSummary":"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.","generatedAt":"2026-09-21T12:44:28.234229Z","generator":"patch2vuln.py","model":"qwen3.8:27b","modelComparison":{"rankings":[{"agreementScore":9,"assumptionCount":5,"confidence":"medium","model":"qwen3.8:27b","score":5}],"selectedModel":"qwen3.8:27b","selectionMethod":"deterministic-consensus-v1","selectionNotice":"The selected result is closest to model consensus; this heuristic does not establish factual correctness and human review remains required."},"patchSha256":"9b7cc757cbbc8a4dd7491c6388e0ee12057c790bb6ca21e10b1d78209bbb7748","patchSummary":"In app/Model/WorkflowModules/action/Module_blocklist_action.php, five lines are inserted after the existing basename() call. The added code defines an $allowedExtensions array containing 'txt', 'list', 'blocklist', and 'csv', extracts the file extension via pathinfo() with PATHINFO_EXTENSION, and performs a strict (===) in_array() check. If the extension is not in the whitelist, the method returns early with a failure message 'Blocklist filename has an invalid extension.' This check is placed before the existing empty/dot filename validation.","patchTruncated":false,"patches":[{"commit":"e5a9431784b4a78faddc0cc6efc2a287f2fd3d08","patchSha256":"9b7cc757cbbc8a4dd7491c6388e0ee12057c790bb6ca21e10b1d78209bbb7748","source":"https://github.com/MISP/MISP/commit/e5a943178.patch","sourceUrl":"https://github.com/MISP/MISP/commit/e5a943178.patch","subject":"fix: [security] arbitrary script execution via insufficient"}],"source":"https://github.com/MISP/MISP/commit/e5a943178.patch","subject":"fix: [security] arbitrary script execution via insufficient","tagVersionBoundary":{"commits_after_fix":142,"repository":"https://github.com/MISP/MISP","tag":"v2.5.47","version":"2.5.47","version_type":"semver"},"weaknessRationale":[{"cweId":"CWE-434","rationale":"The blocklist filename parameter accepted arbitrary file extensions without restriction. A site admin could supply a filename with a dangerous extension (e.g., .php) that would be placed in a web-accessible export directory, enabling script execution. The fix restricts extensions to a safe whitelist, which is the canonical remediation for CWE-434."},{"cweId":"CWE-20","rationale":"The filename parameter was not validated against a set of acceptable values (extensions). Only path stripping and empty-string checks were performed, leaving the extension entirely unvalidated. This is a general improper input validation weakness that enabled the more specific dangerous-file-type issue."}]}}},"recordType":"advisory","vulnId":"GCVE-1-2026-20009"}]}},"cveMetadata":{"assignerOrgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","assignerShortName":"CIRCL","cveId":"CVE-2026-94383","datePublished":"2026-09-21T12:52:03.355Z","dateReserved":"2026-09-21T12:52:01.101Z","dateUpdated":"2026-09-21T12:52:03.355Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-21 13:17:13","lastModifiedDate":"2026-09-21 13:17:13","problem_types":["CWE-20","CWE-434","CWE-434 CWE-434 Unrestricted Upload of File with Dangerous Type","CWE-20 CWE-20 Improper Input Validation"],"metrics":{"cvssMetricV40":[{"source":"5a6e4751-2f3f-4070-9419-94fb35b644e8","type":"Secondary","cvssData":{"version":"4.0","vectorString":"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/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","baseScore":8.6,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"HIGH","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"94383","Ordinal":"1","Title":"MISP Blocklist Workflow Module: Arbitrary Script Execution via U","CVE":"CVE-2026-94383","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"94383","Ordinal":"1","NoteData":"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.\n\nThe 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.\n\nVersion affected: <2.5.47","Type":"Description","Title":"MISP Blocklist Workflow Module: Arbitrary Script Execution via U"}]}}}