CVE Catalog

CVE-2026-39418

MediumCVSS 5.0
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.20%

10th percentile - higher than 10% of all known CVEs

Summary

MaxKB versions 2.7.1 and below allow bypassing sandbox network protection using socket.sendto() with the MSG_FASTOPEN flag. An authenticated user with tool-editing permissions can reach internal services blocked by the banned hosts configuration.

Risk Assessment

Potential unauthorized access to internal services and bypass of sandbox isolation policies. This may enable further internal network exploration.

Recommendation

Update MaxKB to version 2.8.0. Restrict tool-editing permissions and review banned hosts configuration and network segmentation.

Other vulnerabilities in MaxKB

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS