A vulnerability in Cedar JSON policy templates using the 'is in' scope condition allows malformed slot identifiers to cause linking errors or semantic mismatches. This can lead to policy panics or unintended authorization decisions, such as allowing access that should be forbidden. The issue affects only malformed JSON policies with incorrect slot identifiers in principal and resource constraints. Versions prior to 4.11.1 and 3.4.3 are affected. Patches are available in these fixed versions.