CVE-2026-39419
MaxKB: Sandbox Result Validation Bypass via Tool Output Spoofing
Description
MaxKB is an open-source AI assistant for enterprise. In versions 2.7.1 and below, an authenticated user can bypass sandbox result validation and spoof tool execution results by exploiting Python frame introspection to read the wrapper's UUID from its bytecode constants, then writing a forged result directly to file descriptor 1 (bypassing stdout redirection). By calling sys.exit(0), the attacker terminates the wrapper before it prints the legitimate output, causing the MaxKB service to parse and trust the spoofed response as the genuine tool result. This issue has been fixed in version 2.8.0.
CVSS Vector Breakdown
AV:NAttack VectorAC:HAttack ComplexityPR:LPrivileges RequiredUI:NUser InteractionS:UScopeC:NConfidentialityI:LIntegrityA:NAvailabilityWeaknesses
Affected Products
Attack Graph
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Exploitability
MITRE ATT&CK
3 techniquesReferences
Timeline
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