A flaw was found in FreeIPA. A low-privilege authenticated user can exploit this vulnerability by submitting an oversized One-Time Password (OTP) key value. This oversized key is then decoded and re-encoded without proper size limits, consuming excessive CPU and memory resources. This can lead to a denial of service, degrading the availability of the IPA service.
To mitigate this issue, enforce conservative HTTP request-body limits on the /ipa/session/json endpoint to reject oversized payloads before they reach the vulnerable IPA parameter conversion. Additionally, if operationally feasible, restrict self-managed token creation to trusted users and implement monitoring or rate-limiting for repeated large authenticated requests. Changes to HTTP server configurations or FreeIPA permissions may require service restarts or reloads to take effect.