What happened
NVD published CVE-2026-19243 (CVSS 6.3, Medium) on August 7, 2026, describing an allowlist-bypass command injection in nanobot's shell execution tool.
Why it matters
Shell allowlists are a primary guardrail preventing an LLM agent from executing arbitrary commands; a bypass here defeats the intended safety boundary between agent reasoning and host command execution.
Attack vector
The ExecTool._guard_command/_spawn functions in the Shell Allowlist Handler fail to properly validate commands, allowing a remote attacker (via LLM manipulation) to bypass the allowlist and inject arbitrary OS commands.
Affected systems
HKUDS nanobot ≤ 0.2.1
Mitigation
Upgrade to a patched nanobot release.