This vulnerability (CWE-636) in livebook-dev livebook occurs because the system does not fail securely when a deployment group identifier becomes unresolvable due to deletion during agent disconnection. The Livebook agent caches the deployment group identifier but does not clear it when the group is deleted. The code path handling identity enforcement treats unresolved deployment groups as if identity enforcement is off, resulting in empty identity metadata that defaults to full access. Consequently, any unauthenticated network client can gain full privileged access to the Livebook server, bypassing intended identity enforcement mechanisms. The affected versions are from 0.19.7 up to but not including 0.19.9.

An unauthenticated attacker with network access to the affected Livebook server can gain full privileged access equivalent to a fully privileged organization member. This includes the ability to read sensitive notebooks and secrets, execute arbitrary code on the server runtime, and disrupt server operations. This bypasses Livebook Teams identity enforcement, severely compromising confidentiality, integrity, and availability of the server.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict network access to Livebook servers to trusted clients only and monitor for unusual access patterns. Avoid deleting deployment groups while agents are disconnected to reduce the risk of triggering this issue.