Description

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.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-08-20T11:16:21.417Z",
  "pubdate": "2026-08-20T11:16:21.417Z",
  "executiveSummary": "A resource exhaustion vulnerability exists in FreeIPA involving the processing of One-Time Password (OTP) key values. This vulnerability allows low-privilege authenticated users to cause a denial of service (DoS) condition, impacting the availability of the IPA service. The flaw stems from improper handling of oversized input data during cryptographic encoding and decoding operations. When exploited, the targeted service consumes excessive CPU and memory resources, degrading overall system performance and potentially rendering the service unresponsive to legitimate users. The attack requires low-privilege authentication, meaning an adversary must possess valid credentials within the system to interact with the vulnerable endpoint. Risk implications include service degradation, loss of availability, and potential disruption of identity management operations across dependent systems. Mitigation requires applying vendor-supplied patches or updates that implement strict input validation and size constraints on OTP key processing routines to prevent unbounded resource consumption.",
  "technicalDetails": "The vulnerability resides within the FreeIPA service component responsible for processing One-Time Password (OTP) key values. The root cause of the flaw is the absence of adequate size limits and input validation checks when handling user-supplied OTP key data. Specifically, when an oversized OTP key value is submitted, the application attempts to decode and subsequently re-encode the oversized payload.\nDuring this processing phase, the lack of input bounds enforcement causes the decoding and re-encoding routines to dynamically allocate excessive memory and consume intensive CPU cycles to handle the oversized data structure. Because the application processes the unvalidated payload without preliminary length restrictions, memory allocations scale disproportionately relative to standard operational parameters.\nThe attack flow proceeds as follows: 1. An authenticated attacker with low privileges crafts an oversized OTP key value payload. 2. The attacker submits this payload to the FreeIPA service through standard authenticated API or interface channels. 3. The vulnerable component receives the oversized key and initiates decoding and re-encoding operations without enforcing size constraints. 4. The underlying system experiences severe resource contention as memory and CPU are heavily utilized to process the unbounded data. 5. Excessive resource exhaustion leads to a denial of service (DoS), degrading or halting the availability of the IPA service for other users.\nExploitation prerequisites include low-privilege authentication, as the attacker must successfully authenticate to the FreeIPA environment before submitting the malicious OTP key payload. The network exposure is tied to the accessibility of the FreeIPA authentication and management interfaces. Post-exploitation impact is strictly focused on availability, manifesting as service disruption and resource starvation without direct evidence of remote code execution or unauthorized data access based on the provided description."
}