MaxKB: Sandbox escape via ctypes and unhooked SYS_pkey_mprotect

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Summary

CVECVE-2026-39421
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-14 01:16:04 UTC
Updated2026-04-20 17:35:05 UTC
DescriptionMaxKB 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.

Risk And Classification

Primary CVSS: v3.1 7.4 HIGH from [email protected]

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

EPSS: 0.000860000 probability, percentile 0.246900000 (date 2026-04-21)

Problem Types: CWE-94 | CWE-693 | CWE-693 CWE-693: Protection Mechanism Failure | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.4HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
3.1[email protected]Secondary6.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
3.1CNADECLARED6.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Maxkb Maxkb All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA 1Panel-dev MaxKB affected < 2.8.0 Not specified

References

ReferenceSourceLinkTags
github.com/1Panel-dev/MaxKB/commit/479701a4d2e6059506bad0057a66bed91abb5aef [email protected] github.com Patch
github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0 [email protected] github.com Release Notes
github.com/1Panel-dev/MaxKB/security/advisories/GHSA-9c6w-j7w5-3gf7 [email protected] github.com Vendor Advisory
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