CVE-2026-73196 in FreeIPA
Summary
by MITRE • 08/20/2026
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.
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Analysis
by VulDB Data Team • 08/20/2026
The identified vulnerability in FreeIPA represents a significant resource exhaustion flaw that impacts the stability and availability of identity management services. The core issue stems from an insufficient validation mechanism regarding input size constraints for One-Time Password (OTP) key values. Specifically, when a low-privilege authenticated user submits an OTP key with excessive length or complexity, the system proceeds to decode and re-encode this value without enforcing strict upper bounds on data volume. This lack of boundary checking allows malicious actors to trigger disproportionate computational overhead within the authentication subsystem. The process of decoding and re-encoding large binary blobs consumes significant Central Processing Unit cycles and allocates substantial amounts of Random Access Memory, leading to a state where system resources are rapidly depleted by these specific requests rather than legitimate administrative or user operations.
From an operational perspective, this vulnerability facilitates a Denial of Service attack against the FreeIPA infrastructure. By repeatedly submitting oversized OTP keys, an attacker can saturate server resources, causing latency spikes for all users and potentially crashing critical authentication services. This degradation directly impacts the availability component of the CIA triad, which is fundamental to identity management systems that serve as gatekeepers for organizational access controls. The impact extends beyond simple service interruption; it undermines trust in the integrity of the authentication process and can disrupt dependent applications that rely on FreeIPA for user verification and authorization decisions.
This flaw aligns with Common Weakness Enumeration category CWE-400, which describes Uncontrolled Resource Consumption. It also maps to MITRE ATT&CK technique T1496, specifically representing Resource Hijacking where an adversary uses computing resources as part of their attack strategy to degrade service availability for legitimate users. The vulnerability highlights a critical gap in input validation practices within the OTP module, emphasizing that even authenticated low-privilege accounts possess sufficient access rights to trigger resource-intensive operations if proper safeguards are not implemented at the application layer.
Mitigation strategies must focus on implementing strict size limits and sanitization routines before any decoding or encoding processes occur. Administrators should ensure they apply vendor-provided patches as soon as they become available, as these typically include code changes that enforce maximum length constraints for OTP key inputs. Additionally, deploying Web Application Firewalls with rules designed to detect anomalous payload sizes can provide a layer of defense in depth by blocking oversized requests before they reach the FreeIPA application logic. Regular auditing of authentication logs for patterns indicative of resource exhaustion attacks is also recommended to identify potential exploitation attempts early and maintain service resilience against such denial-of-service vectors.