CVE-2026-39420: CWE-693: Protection Mechanism Failure in 1Panel-dev MaxKB
MaxKB versions 2. 7. 1 and below contain a sandbox bypass vulnerability due to an incomplete sandbox protection mechanism. An authenticated user with tool execution privileges can exploit the ability to run the /usr/bin/env command with the -i flag to clear environment variables, including LD_PRELOAD, which disables the sandbox hooks. This allows the attacker to execute Python code without restrictions, leading to unrestricted remote code execution and network access. The issue is fixed in version 2. 8. 0.
AI Analysis
Technical Summary
MaxKB, an open-source AI assistant for enterprise, uses LD_PRELOAD-based sandboxing to restrict untrusted Python code execution by intercepting sensitive C library functions. However, in versions 2.7.1 and below, the sandbox can be bypassed because the /usr/bin/env utility can be executed with the -i flag, which clears all environment variables including LD_PRELOAD. This disables the sandbox hooks, allowing an attacker with tool execution privileges to spawn a native Python process without restrictions, resulting in unrestricted remote code execution and network access. This vulnerability is identified as CVE-2026-39420 and is classified under CWE-693 (Protection Mechanism Failure) and CWE-78 (Improper Neutralization of Special Elements used in an OS Command). The vulnerability has a CVSS 3.1 score of 6.3 (medium severity). It is fixed in MaxKB version 2.8.0.
Potential Impact
An authenticated user with tool execution privileges can bypass the sandbox protection by clearing environment variables, enabling unrestricted remote code execution and network access. This compromises the intended security restrictions on untrusted Python code execution, potentially allowing malicious actions within the enterprise environment where MaxKB is deployed.
Mitigation Recommendations
Upgrade MaxKB to version 2.8.0 or later, where this sandbox bypass vulnerability has been fixed. Since no official patch links or vendor advisory are provided, confirm the upgrade from the official 1Panel-dev sources. Until upgraded, restrict tool execution privileges to trusted users only to minimize risk.
CVE-2026-39420: CWE-693: Protection Mechanism Failure in 1Panel-dev MaxKB
Description
MaxKB versions 2. 7. 1 and below contain a sandbox bypass vulnerability due to an incomplete sandbox protection mechanism. An authenticated user with tool execution privileges can exploit the ability to run the /usr/bin/env command with the -i flag to clear environment variables, including LD_PRELOAD, which disables the sandbox hooks. This allows the attacker to execute Python code without restrictions, leading to unrestricted remote code execution and network access. The issue is fixed in version 2. 8. 0.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
MaxKB, an open-source AI assistant for enterprise, uses LD_PRELOAD-based sandboxing to restrict untrusted Python code execution by intercepting sensitive C library functions. However, in versions 2.7.1 and below, the sandbox can be bypassed because the /usr/bin/env utility can be executed with the -i flag, which clears all environment variables including LD_PRELOAD. This disables the sandbox hooks, allowing an attacker with tool execution privileges to spawn a native Python process without restrictions, resulting in unrestricted remote code execution and network access. This vulnerability is identified as CVE-2026-39420 and is classified under CWE-693 (Protection Mechanism Failure) and CWE-78 (Improper Neutralization of Special Elements used in an OS Command). The vulnerability has a CVSS 3.1 score of 6.3 (medium severity). It is fixed in MaxKB version 2.8.0.
Potential Impact
An authenticated user with tool execution privileges can bypass the sandbox protection by clearing environment variables, enabling unrestricted remote code execution and network access. This compromises the intended security restrictions on untrusted Python code execution, potentially allowing malicious actions within the enterprise environment where MaxKB is deployed.
Mitigation Recommendations
Upgrade MaxKB to version 2.8.0 or later, where this sandbox bypass vulnerability has been fixed. Since no official patch links or vendor advisory are provided, confirm the upgrade from the official 1Panel-dev sources. Until upgraded, restrict tool execution privileges to trusted users only to minimize risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-07T00:23:30.595Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69dd958882d89c981f9c5820
Added to database: 4/14/2026, 1:16:56 AM
Last enriched: 4/14/2026, 1:32:20 AM
Last updated: 4/14/2026, 3:23:56 AM
Views: 4
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