CVE-2026-61483 in Lucy
Summary
by MITRE • 08/05/2026
** UNSUPPORTED WHEN ASSIGNED ** Uncontrolled Recursion vulnerability in Apache Lucy.
This issue affects Apache Lucy: all versions.
As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users.
NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
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Analysis
by VulDB Data Team • 08/05/2026
The uncontrolled recursion vulnerability in Apache Lucy represents a critical design flaw that can lead to system instability and potential denial of service conditions. This vulnerability exists within the core indexing and search functionality of the Apache Lucy search engine library, where recursive function calls are not properly bounded or monitored. The flaw manifests when malformed or malicious input data triggers iterative processing patterns that escalate exponentially without proper termination conditions.
From a technical perspective, this vulnerability aligns with CWE-674, which specifically addresses uncontrolled recursion in software systems. The issue occurs at the algorithmic level where recursive data structures or method calls lack adequate base case validation or stack depth monitoring mechanisms. When Apache Lucy processes certain input patterns that trigger recursive parsing or indexing operations, the system can exhaust available stack memory and eventually crash or become unresponsive.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack vectors. While the primary risk is denial of service through resource exhaustion, attackers could leverage this weakness in environments where Apache Lucy is integrated into larger applications. The vulnerability affects all versions of the library, indicating a fundamental flaw in the architectural design rather than a specific implementation error that might have been patched in later releases.
According to ATT&CK framework category T1499, this vulnerability falls under the "Endpoint Denial of Service" tactic where adversaries can consume system resources to prevent legitimate use of services. The attack surface becomes particularly concerning when Apache Lucy is deployed in web applications or search-heavy systems where user input directly feeds into the indexing process.
Security practitioners should recognize that this vulnerability exists in a retired project, meaning no official patches or updates will be forthcoming from the maintainers. Organizations relying on Apache Lucy must implement compensating controls such as input sanitization, rate limiting, and access restrictions to trusted users only. The recommended mitigation strategy involves restricting system access through network segmentation, implementing robust input validation mechanisms, and monitoring for anomalous recursive processing patterns that might indicate exploitation attempts.
The broader implications highlight the importance of proper resource management in library design and the risks associated with continuing to use unsupported software components. Legacy systems often contain such vulnerabilities that remain unpatched due to compatibility concerns or lack of maintenance resources. Organizations should conduct comprehensive inventory assessments to identify all instances of Apache Lucy and other retired software components, ensuring appropriate risk mitigation strategies are implemented before they can be exploited in production environments.
Given the nature of recursion-based vulnerabilities, defensive measures should include implementing maximum recursion depth limits, establishing memory monitoring thresholds, and deploying automated alerting systems that can detect unusual processing patterns. The vulnerability serves as a reminder that even seemingly simple architectural components can contain critical flaws when proper safeguards are not implemented during initial development phases.