CVE-2023-47634 in Decidim
Summary
by MITRE • 02/29/2024
Decidim is a participatory democracy framework. Starting in version 0.10.0 and prior to versions 0.26.9, 0.27.5, and 0.28.0, a race condition in the endorsement of resources (for instance, a proposal) allows a user to make more than once endorsement. To exploit this vulnerability, the request to set an endorsement must be sent several times in parallel. Versions 0.26.9, 0.27.5, and 0.28.0 contain a patch for this issue. As a workaround, disable the Endorsement feature in the components.
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Analysis
by VulDB Data Team • 02/15/2025
The vulnerability identified as CVE-2023-47634 affects Decidim, an open-source participatory democracy framework designed to facilitate citizen engagement in democratic processes. This race condition vulnerability specifically targets the endorsement mechanism within the platform, which allows users to submit multiple endorsements for the same resource such as proposals or initiatives. The flaw exists in versions starting from 0.10.0 up to and including the vulnerable releases prior to 0.26.9, 0.27.5, and 0.28.0, creating a significant security gap in the platform's integrity controls. The vulnerability stems from insufficient concurrency management during the endorsement process, where parallel request handling fails to properly validate or lock the endorsement state before processing multiple simultaneous requests.
The technical implementation of this race condition occurs when users submit endorsement requests in parallel to the same resource, exploiting the lack of proper synchronization mechanisms within the framework's database transactions or state management. This flaw allows malicious actors or even ordinary users to bypass intended limitations on individual endorsements, potentially skewing participation metrics and undermining the democratic process integrity. The vulnerability specifically targets the backend processing logic where endorsement counts are incremented and validated, creating a window of opportunity for concurrent requests to interfere with each other's processing. According to CWE classification, this represents a race condition vulnerability under CWE-362, which occurs when two or more threads or processes access shared resources concurrently without proper synchronization, leading to unpredictable behavior and potential security implications.
The operational impact of this vulnerability extends beyond simple metric manipulation to potentially compromise the fundamental principles of participatory democracy that Decidim aims to support. When users can submit multiple endorsements for the same resource, it creates false representation of community support and can manipulate voting outcomes or visibility rankings of proposals. This undermines trust in the platform's data integrity and potentially affects decision-making processes that rely on accurate endorsement counts. The vulnerability particularly affects democratic mechanisms where each user is intended to have only one endorsement per resource, making the system susceptible to manipulation through parallel request exploitation. From an attack perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves data manipulation through race conditions and concurrency issues.
The security implications of this vulnerability are significant for organizations relying on Decidim for participatory governance, as it could enable systematic manipulation of public participation data and potentially influence policy decisions based on falsified endorsement metrics. The patch releases 0.26.9, 0.27.5, and 0.28.0 address this issue through proper synchronization mechanisms that ensure endorsement operations are atomic and prevent concurrent processing of the same endorsement request. Organizations should implement immediate mitigations by disabling the endorsement feature in affected components until the patched versions are deployed, as recommended in the vulnerability advisory. The fix typically involves implementing proper database locking mechanisms, transaction isolation levels, or application-level concurrency controls to ensure that endorsement operations complete successfully before allowing additional endorsements for the same resource. This vulnerability highlights the importance of proper concurrency control in web applications handling user participation metrics and demonstrates how seemingly simple features can become security risks when not properly synchronized across concurrent operations.