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CVE-2026-39421

MaxKB: Sandbox escape via ctypes and unhooked SYS_pkey_mprotect

Published: Apr 14, 2026Updated: Apr 20, 2026 Sources: CVE List NVDCWE-94
NVD MITRE
6.3CVSSMEDIUM
EPSS Score
0.3%
Top 82.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:LI:LA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:LAvailability
Low
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Weaknesses

CWE-94CWE-693

Affected Products

maxkbmaxkb
On-prem
Enterprise Software / collaboration-groupware
MaxKB1Panel-dev
On-prem
Cloud & SaaS / cloud-platform
maxkbEnterprise Softwareaka maxkb
1panel-devoss-projectCNCloud & SaaSaka 1panel

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://github.com/1Panel-dev/MaxKB/commit/479701a4d2e6059506bad0057a66bed91abb5aef
github.com
https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0
github.com
https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-9c6w-j7w5-3gf7
github.com

Timeline

Published
Apr 14, 2026
Last Updated
Apr 20, 2026

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