What’s Vulnerable › Vulnerabilities

CVE-2026-39419: MaxKB: Sandbox Result Validation Bypass via Tool Output Spoofing

• Severity: low (CVSS 3.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-14 · updated 2026-10-26
• Weakness: CWE-74

Description

MaxKB is an open-source AI assistant for enterprise. In versions 2.7.1 and below, an authenticated user can bypass sandbox result validation and spoof tool execution results by exploiting Python frame introspection to read the wrapper's UUID from its bytecode constants, then writing a forged result directly to file descriptor 1 (bypassing stdout redirection). By calling sys.exit(0), the attacker terminates the wrapper before it prints the legitimate output, causing the MaxKB service to parse and trust the spoofed response as the genuine tool result. This issue has been fixed in version 2.8.0.

Affected products

• 1Panel-dev MaxKB: before 2.8.0 — fixed in 2.8.0

How to fix

Upgrade to a fixed version: 1Panel-dev MaxKB 2.8.0. Check the vendor advisory for mitigations.

References

• https://github.com/1Panel-dev/MaxKB/commit/38c4cfecd065293ede0437f6fa76cf0116591d25
• https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0
• https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-f3c8-p474-xwfv

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