CVE-2026-39419 MaxKB: Sandbox Result Validation Bypass via Tool Output Spoofing
Authenticated users can bypass sandbox validation and spoof tool execution results in MaxKB, leading to trusted data manipulation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-39419?
CVE-2026-39419 is a low-severity vulnerability in 1Panel-dev MaxKB, published on 14 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-39419?
It affects 1 product.
Products include Maxkb Maxkb.
How do I fix CVE-2026-39419?
No fix has been published for CVE-2026-39419 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-39419 being exploited?
There is no known exploitation of CVE-2026-39419 in the wild and no public exploit code.
Other vulnerabilities in 1Panel-dev MaxKB
- CVE-2025-66419 MaxKB vulnerable to privilege escalation through sandbox bypass
- CVE-2025-66446 MaxKB has a Python sandbox LD_PRELOAD bypass
- CVE-2025-64511 MaxKB has SSRF in sandbox
- CVE-2026-39422 MaxKB has Stored XSS via ChatHeadersMiddleware
- CVE-2026-39423 Stored XSS via Eval Injection in EchartsRander Component
Sources
Also known as GHSA-f3c8-p474-xwfv.