1Panel-dev MaxKB up to 2.7.x socket.sendto server-side request forgery

Summaryinfo

A vulnerability described as critical has been identified in 1Panel-dev MaxKB up to 2.7.x. This affects the function socket.sendto. The manipulation results in server-side request forgery. This vulnerability is reported as CVE-2026-39418. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, was found in 1Panel-dev MaxKB up to 2.7.x. Affected is the function socket.sendto. The manipulation with an unknown input leads to a server-side request forgery vulnerability. CWE is classifying the issue as CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-39418 since 04/07/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit.

Upgrading to version 2.8.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 4d06362750b15390437f1d2e4d14ec79baef8559 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• 1Panel-dev

Name

• MaxKB

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7

License

• open-source

Website

• Product: https://github.com/1Panel-dev/MaxKB/

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