CVE-2026-39421 json
MaxKB: Sandbox escape via ctypes and unhooked SYS_pkey_mprotect
published 2026-04-14 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-22180
- cvss
- 6.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 18%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- maxkb maxkb 2.8.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L |
| NVD | 3.1 | 7.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L |
Affected products
- 1Panel-dev MaxKB
Classification
References
Sources
- CVE List CVE-2026-39421
- NVD CVE-2026-39421
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.