CVE-2026-39419 Details
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.
A vulnerability in MaxKB versions through 2.7.1 allows authenticated users to bypass sandbox result validation and spoof tool execution results. This is achieved by exploiting Python frame introspection to extract the wrapper's UUID from its bytecode constants. The attacker can then write a forged result directly to the standard output, bypassing the usual redirection. By calling sys.exit(0), the attacker terminates the wrapper execution before the legitimate output is printed, causing the MaxKB service to accept the spoofed response as the genuine tool result.
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-290 | Authentication Bypass by Spoofing | [email protected] |
| CWE-693 | Protection Mechanism Failure | [email protected] |
| CWE-74 | Improper Neutralization of Special Elements in Output Used by a Downstream Component ('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] |