CVE-2026-39420
6.3 · MEDIUMOverview
CVE-2026-39420 is a medium-severity vulnerability affecting maxkb maxkb. It was published on April 14, 2026 and has a CVSS 3.1 base score of 6.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
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 n
Remediation
Check the references section for vendor advisories and patches from maxkb. Update maxkb to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| maxkb | maxkb | >= 0, < 2.8.0 | Affected |
Frequently Asked Questions
What is CVE-2026-39420?
CVE-2026-39420 is a medium-severity vulnerability affecting maxkb maxkb. It was published on April 14, 2026 and has a CVSS 3.1 base score of 6.3 (MEDIUM).
How severe is CVE-2026-39420?
This vulnerability has a CVSS 3.1 base score of 6.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-39420?
Check the references section for vendor advisories and patches from maxkb. Update maxkb to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-39420?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-39420 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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