PT-2026-32574 · 1Panel Dev · Maxkb

Liqiang-Fit2Cloud

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Published

2026-04-14

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Updated

2026-04-14

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CVE-2026-39420

CVSS v3.1

6.3

Medium

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
MaxKB is an open-source AI assistant for enterprise. In versions 2.7.1 and below, an incomplete sandbox protection mechanism allows an authenticated user with tool execution privileges to escape the LD PRELOAD-based sandbox. By env command the attacker can clear the environment variables and drop the sandbox.so hook, leading to unrestricted Remote Code Execution (RCE) and network access. MaxKB restricts untrusted Python code execution via the Tool Debug API by injecting sandbox.so through the LD PRELOAD environment variable. This intercepts sensitive C library functions (like execve, socket, open) to restrict network and file access. However, a patch allowed the /usr/bin/env utility to be executed by the sandboxed user. When an attacker is permitted to create subprocesses, they can execute the env -i python command. The -i flag instructs env to completely clear all environment variables before running the target program. This effectively drops the LD PRELOAD environment variable. The newly spawned Python process will therefore execute natively without any sandbox hooks, bypassing all network and file system restrictions. This issue has been fixed in version 2.8.0.

Fix

OS Command Injection

Protection Mechanism Failure

Weakness Enumeration

CWE-78CWE-693

Related Identifiers

CVE-2026-39420

Affected Products

Maxkb