Observable response discrepancy in PostgreSQL SCRAM authentication allows an unauthenticated user to test the existence of a user via observing the SCRAM iteration count. This requires the probed user to have a non-default scram_iterations count, because the authentication challenge for a nonexistent user reports the default scram_iterations. Within major versions 16-18, minor versions before PostgreSQL 18.6, 17.11, and 16.15 are affected. Versions before PostgreSQL 16 are unaffected.
| Version | Score | Severity | Vector String |
|---|---|---|---|
| 3.1 | 5.3 | Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |