CVE-2025-53927 Overview
CVE-2025-53927 is a sandbox escape vulnerability in MaxKB, an open-source enterprise AI assistant developed by 1Panel. The flaw exists in versions prior to 2.0.0 because the sandbox restricts execution permissions only within a specific directory. An authenticated attacker can invoke Python's shutil.copy2 method to copy arbitrary binaries into the executable directory, bypassing directory-based restrictions. Successful exploitation enables command execution and reverse shell scenarios from within the sandboxed Python environment. The vulnerability is classified under [CWE-94] (Improper Control of Generation of Code). MaxKB version 2.0.0 addresses the flaw.
Critical Impact
Authenticated attackers can escape the MaxKB Python sandbox, execute arbitrary commands, and establish reverse shells on the host running the AI assistant.
Affected Products
- MaxKB (1Panel-dev/MaxKB) all versions prior to 2.0.0
- MaxKB LTS distributions matching cpe:2.3:a:maxkb:maxkb:*:*:*:*:lts:*:*:*
- Deployments using the built-in Python function execution sandbox
Discovery Timeline
- 2025-07-17 - CVE-2025-53927 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-53927
Vulnerability Analysis
MaxKB exposes a Python execution sandbox that allows workflow authors to run custom functions supporting AI assistant tooling. The sandbox enforces isolation by limiting execution permissions to files residing in a specific directory. However, the enforcement is scoped to execute permissions on files already present in that directory rather than restricting the file operations available inside the interpreter itself. Because shutil.copy2 remains reachable from sandboxed Python code, an attacker can stage an arbitrary executable inside the trusted directory and then invoke it. This turns a directory-scoped permission model into an arbitrary command execution primitive. The issue is a design-level control failure rather than a memory corruption bug.
Root Cause
The root cause is incomplete sandbox design. MaxKB validates where executables can run but does not restrict the file-system APIs that populate that trusted location. Allowing shutil.copy2 inside the sandbox lets attackers promote untrusted binaries into the execution allowlist. The fix in v2.0.0 tightens the sandbox to prevent this bypass.
Attack Vector
Exploitation requires local, authenticated access with privileges to submit or edit function definitions the sandbox will execute. The attacker crafts a function that uses shutil.copy2 to copy a system binary or attacker-supplied payload into the sandboxed executable directory, then triggers execution to spawn a reverse shell or run arbitrary commands. See the GitHub Security Advisory GHSA-5xhm-4j3v-87m4 for the vendor description.
No verified proof-of-concept code is published. The advisory describes the mechanism in prose only.
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Stop Identity AttacksDetection Methods for CVE-2025-53927
Indicators of Compromise
- Unexpected files copied into the MaxKB sandbox executable directory, particularly binaries whose hashes match system utilities such as /bin/sh, /bin/bash, or nc.
- Sandbox worker processes spawning child processes that initiate outbound network connections to non-MaxKB destinations.
- Python execution logs referencing shutil.copy2 calls originating from user-defined function nodes.
Detection Strategies
- Monitor the MaxKB sandbox directory for file-write events and correlate them with the process identity of the sandbox worker.
- Alert on any process descended from the MaxKB Python runtime that executes shell interpreters or opens sockets to external hosts.
- Review MaxKB function definitions for references to shutil, subprocess, os.system, or ctypes that would not normally appear in AI assistant tooling.
Monitoring Recommendations
- Enable audit logging on the container or host filesystem paths used by the MaxKB sandbox to capture new executable creations.
- Baseline outbound network egress from the MaxKB service and alert on connections to non-approved destinations.
- Track authentication events for MaxKB accounts with function-editing privileges and flag anomalous sessions.
How to Mitigate CVE-2025-53927
Immediate Actions Required
- Upgrade MaxKB to version 2.0.0 or later using the GitHub MaxKB Release 2.0.0 artifacts.
- Rotate credentials for any MaxKB accounts with function-editing privileges after patching.
- Inspect the sandbox executable directory for unexpected binaries and remove any that were not deployed by administrators.
Patch Information
The vendor addressed CVE-2025-53927 in MaxKB v2.0.0. The release notes and download artifacts are available at the GitHub MaxKB Release 2.0.0 page, and the coordinated advisory is documented in GitHub Security Advisory GHSA-5xhm-4j3v-87m4.
Workarounds
- Restrict access to the MaxKB function editor to trusted administrators until the patch is applied.
- Run MaxKB inside a container with a read-only filesystem overlay on the sandbox executable directory to prevent unauthorized file copies.
- Apply outbound network egress filtering on the MaxKB host so sandboxed processes cannot reach attacker-controlled reverse shell listeners.
# Configuration example
# Upgrade MaxKB to the patched release
docker pull 1panel/maxkb:v2.0.0
docker stop maxkb && docker rm maxkb
docker run -d --name=maxkb \
--read-only \
--tmpfs /tmp:rw,noexec,nosuid \
-p 8080:8080 \
1panel/maxkb:v2.0.0
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
