CVE & CISA-KEV Catalog

CVE-2026-39421

MEDIUM
6.3
CVSS v3
NVD

Description

MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a sandbox escape vulnerability in the ToolExecutor component. By leveraging Python's ctypes library to execute raw system calls, an authenticated attacker with workspace privileges can bypass the LD_PRELOAD-based sandbox.so module to achieve arbitrary code execution via direct kernel system calls, enabling full network exfiltration and container compromise. The library intercepts critical standard system functions such as execve, system, connect, and open. It also intercepts mprotect to prevent PROT_EXEC (executable memory) allocations within the sandboxed Python processes, but pkey_mprotect is not blocked. This issue has been fixed in version 2.8.0.

CWE-94Code InjectionCWE-693Protection Mechanism Failure

How to fix

Remediation Available
maxkbNVD
Affected:< 2.8.0Fixed in:2.8.0CVE-2026-39421derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityLow
IntegrityLow
AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Exploit Intelligence

0.26%probability of exploitation in 30 days
18thpercentile

Low risk: more likely to be exploited than 18% of all known CVEs.

References

Vendor Advisory1
Release Notes1

Related Vulnerabilities

Other CWE-94 (Code Injection) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2017-9841Critical9.8100%KEVFix
CVE-2015-1635Critical9.8100%KEV-
CVE-2022-22954Critical9.8100%KEV + Ransom-
CVE-2021-22204Medium6.8100%KEVFix
CVE-2025-3248Critical9.8100%KEVFix
CVE-2012-0158High8.8100%KEV-
Embed a live status badge for CVE-2026-39421
CVE-2026-39421 severity badge

Markdown

[![CVE-2026-39421](https://tridentstack.com/cve/badge/CVE-2026-39421.svg)](https://tridentstack.com/cve/CVE-2026-39421)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-39421"><img src="https://tridentstack.com/cve/badge/CVE-2026-39421.svg" alt="CVE-2026-39421"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-20.