CVE-2026-39418

HIGH EPSS 9.8%
Published Apr 14, 20262mo ago · Modified Jun 17, 20261w ago
7.4 CVSS 3.1
High
Find Similar
Published Apr 14, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

Description

MaxKB is an open-source AI assistant for enterprise. In versions 2.7.1 and below, sandbox network protection can be bypassed by using socket.sendto() with the MSG_FASTOPEN flag. This allows authenticated user with tool-editing permissions to reach internal services that are explicitly blocked by the sandbox's banned hosts configuration. MaxKB's sandbox uses LD_PRELOAD to hook the connect() function and block connections to banned IPs, but Linux's sendto() with the MSG_FASTOPEN flag can establish TCP connections directly through the kernel without ever calling connect(), completely bypassing the IP validation. Although sendto is listed in the syscall() wrapper, this is ineffective because glibc invokes the kernel syscall directly rather than routing through the hooked syscall() function. This issue has been fixed in version 2.8.0.

CVSS Details

Base Score
7.4
Exploitability
3.1
Impact
3.7
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Changed
Confidentiality Low
Integrity Low
Availability Low

Threat Intelligence

EPSS Exploit Probability
9.8% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-918 Server-Side Request Forgery (SSRF) Validation

Affected Products 1

VendorProductVersionRange
maxkbmaxkb* <2.8.0

References 3

  • github.com https://github.com/1Panel-dev/MaxKB/commit/4d06362750b15390437f1d2e4d14ec79baef8559
    Patch
  • github.com https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0
    Release Notes
  • github.com https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-w9g4-q3gm-6q6w
    Vendor Advisory

Remediation

  • github.com https://github.com/1Panel-dev/MaxKB/commit/4d06362750b15390437f1d2e4d14ec79baef8559
    Patch