CVE-2026-39421 Details
Description
MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a sandbox escape vulnerability in the ToolExecutor component. By leveraging Python's ctypes library to execute raw system calls, an authenticated attacker with workspace privileges can bypass the LD_PRELOAD-based sandbox.so module to achieve arbitrary code execution via direct kernel system calls, enabling full network exfiltration and container compromise. The library intercepts critical standard system functions such as execve, system, connect, and open. It also intercepts mprotect to prevent PROT_EXEC (executable memory) allocations within the sandboxed Python processes, but pkey_mprotect is not blocked. This issue has been fixed in version 2.8.0.
A sandbox escape vulnerability has been identified in MaxKB, an open-source AI assistant for enterprise, specifically in versions through 2.7.1. The issue resides in the ToolExecutor component, where an authenticated attacker with workspace privileges can exploit Python's ctypes library to execute raw system calls. This exploitation bypasses the LD_PRELOAD-based sandbox module, leading to arbitrary code execution via direct kernel system calls. The vulnerability allows for full network exfiltration and container compromise. The sandbox fails to block modern system calls like SYS_pkey_mprotect, which can be exploited to manipulate memory protections and execute unauthorized system calls, circumventing the intended security measures.
Users can upgrade to MaxKB version 2.8.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 14, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-693 | Protection Mechanism Failure | [email protected] |
| CWE-94 | Improper Control of Generation of Code ('Code Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| maxkb maxkb | < 2.8.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 20, 2026 | Initial Analysis | [email protected] |
| Apr 14, 2026 | New CVE Received | [email protected] |