AIKIDO-2026-110518

TL;DR

The encode_permissions!/1 function generated by use Guardian.Permissions in lib/guardian/permissions.ex calls String.to_atom on every key of the supplied map before validating it against the configured permission set. Keys with integer values skip validation entirely, so unknown keys are interned as new atoms with no error raised. Because BEAM atoms are never garbage collected and the atom table is a fixed-size resource, an application that passes an externally influenced permissions map into token issuance lets a single request mint unbounded atoms and crash the node. The fix validates keys against the permission set and resolves lookups through String.to_existing_atom.