First finding, and it establishes the record format by being one. Kept minimal
on purpose - inventing a schema before there is a second finding to test it
against would be designing in the dark.
The substance: POST /v1/check and /v1/batch_check authenticate no caller, so
any workload with network reach can assert any subject and any tenant and
receive an authoritative allow from the estate's authorization oracle.
Self-reported by flex-auth during their Tenancy Posture review, and their own
note says they did not know they were carrying it.
Severity, disclosure and escalation are left unset. Per INTENT this repo owns
those and the reporter does not, and filling them in as the routing party would
collapse the separation on the first record.
Two things stated rather than assumed. Exposure depends on whether a
default-deny NetworkPolicy fronts the service; flex-auth did not say, and I did
not check, because that would be reporting on a system I do not own. And the
disclosure question is genuinely live here - build mode is public-by-default,
this is a live authorization bypass, and the controlled-disclosure mechanism
this repo anticipates does not exist yet, so the choice today is publish or
hold with nothing in between.
Three related defects from the same review round are recorded as visible but
not filed, since filing them was not asked for. All four were found by repos
reading their own code against a ladder within a day of each other, and none
was found by monitoring - which is itself a fact worth carrying into triage.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
tegwick
97762a4be0