PT-2026-32573 · 1Panel Dev · Maxkb

Liqiang · Published 2026-04-14 · Updated 2026-04-14 · CVE-2026-39418

Mitre

CVSS v3.1

5.0

Medium

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

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.

Fix

SSRF

Weakness Enumeration

CWE-918

Related Identifiers

CVE-2026-39418

Affected Products

Maxkb

References · 7

• https://nvd.nist.gov/vuln/detail/CVE-2026-39418 · Security Note
• https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-w9g4-q3gm-6q6w · Note
• https://github.com/1Panel-dev/MaxKB/commit/4d06362750b15390437f1d2e4d14ec79baef8559 · Note
• https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0 · Note
• https://twitter.com/VulmonFeeds/status/2043993264944980347 · Twitter Post
• https://twitter.com/CVEarity/status/2044087197251645588 · Twitter Post
• https://twitter.com/CVEnew/status/2043976157477863723 · Twitter Post