CVE-2024-38360 in Discourse
Summary
by MITRE • 07/15/2024
Discourse is an open source platform for community discussion. In affected versions by creating replacement words with an almost unlimited number of characters, a moderator can reduce the availability of a Discourse instance. This issue has been addressed in stable version 3.2.3 and in current betas. Users are advised to upgrade. Users unable to upgrade may manually remove the long watched words either via SQL or Rails console.
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Analysis
by VulDB Data Team • 08/27/2025
CVE-2024-38360 represents a denial of service vulnerability within the Discourse community discussion platform that stems from inadequate input validation for replacement word functionality. This flaw exists in the moderation system where administrators can define replacement words to automatically substitute inappropriate content within posts. The vulnerability allows a malicious moderator or attacker with sufficient privileges to create replacement words containing an excessive number of characters, potentially leading to resource exhaustion and system unavailability. The issue manifests when the platform processes these excessively long replacement words during content filtering operations, consuming disproportionate system resources and potentially causing memory allocation failures or process timeouts.
The technical implementation of this vulnerability relates to CWE-770, which addresses allocation of resources without limits or throttling, and CWE-400, concerning unspecified resource management issues. The root cause lies in the lack of proper input sanitization and length validation for user-defined replacement words within the moderation subsystem. When these long strings are processed through the discourse filtering engine, they trigger cascading resource consumption that can degrade system performance or cause complete service interruption. The vulnerability operates at the application layer and requires moderate privileges to exploit, specifically the ability to create or modify replacement word configurations within the moderation interface.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential business continuity issues for organizations relying on Discourse for community engagement and communication. Attackers could leverage this weakness to target specific Discourse instances, causing availability degradation that affects legitimate users and community members. The vulnerability affects all versions prior to 3.2.3 and current beta releases, making it particularly concerning for organizations with delayed upgrade cycles or those operating in regulated environments where service availability is critical. System administrators may observe performance degradation, increased memory usage, or complete service unavailability during peak usage periods when the malicious replacement words are processed.
Mitigation strategies for CVE-2024-38360 include immediate upgrade to Discourse version 3.2.3 or later, which implements proper input validation and character limit enforcement for replacement words. Organizations unable to perform immediate upgrades should manually remediate the issue by accessing the database through SQL commands or Rails console to identify and remove existing long replacement words from the system. The recommended approach involves querying the relevant database tables containing replacement word configurations and deleting entries exceeding established character limits. Additionally, implementing proper access controls and privilege separation can limit the potential impact of compromised moderator accounts. Security monitoring should include detection of unusual replacement word creation patterns and automated alerts for configuration changes that exceed predefined thresholds, aligning with ATT&CK technique T1548.001 for privilege escalation and T1499.004 for network denial of service.
Organizations should also consider implementing rate limiting and resource consumption monitoring for moderation operations, particularly around content filtering processes. The vulnerability demonstrates the importance of validating user inputs and implementing proper resource constraints even for administrative functions within web applications. Regular security assessments of community platforms should include review of privilege escalation paths and input validation mechanisms to prevent similar issues from arising in other components of the system architecture.