CVE-2025-11042 in Community Edition
Summary
by MITRE • 09/26/2025
An issue was discovered in GitLab CE/EE affecting all versions starting from 17.2 before 18.2.7, 18.3 before 18.3.3, and 18.4 before 18.4.1, that allows an attacker to cause uncontrolled CPU consumption, potentially leading to a Denial of Service (DoS) condition while using specific GraphQL queries.
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Analysis
by VulDB Data Team • 09/30/2025
This vulnerability in GitLab CE/EE represents a critical denial of service weakness that stems from insufficient input validation within the GraphQL query processing mechanism. The flaw exists in versions beginning with 17.2 through 18.4.0, specifically affecting systems that process complex GraphQL requests with nested fields and recursive queries. Attackers can exploit this vulnerability by crafting malicious GraphQL queries that trigger excessive computational overhead, causing the GitLab instance to consume disproportionate CPU resources. The vulnerability manifests when the system attempts to resolve deeply nested queries or queries with recursive field references that are not properly bounded or limited by the GraphQL execution engine. This allows an attacker to consume system resources at an exponential rate, potentially leading to complete service unavailability for legitimate users. The issue is particularly dangerous because GraphQL queries can be constructed to create combinatorial explosions in the number of operations required to resolve a single request, making it difficult to predict and prevent such attacks through simple rate limiting approaches.
The technical implementation of this vulnerability aligns with CWE-400, which describes uncontrolled resource consumption, and specifically relates to improper input validation in query processing systems. From an operational perspective, this vulnerability exposes GitLab instances to attacks that can be executed with minimal privileges, as the GraphQL endpoint is typically accessible to authenticated users or even anonymous users depending on the instance configuration. The attack vector involves sending specially crafted GraphQL queries that contain deeply nested fields or recursive references, which cause the GraphQL resolver to perform excessive computation. The system's response to these queries results in sustained high CPU utilization, often reaching 100% of available processing power on affected nodes. This behavior can persist for extended periods, allowing attackers to maintain the denial of service condition until the system is manually restarted or the queries are modified.
The impact of this vulnerability extends beyond simple service disruption as it can affect the entire GitLab infrastructure, potentially causing cascading failures in dependent services that rely on GitLab's API endpoints. Organizations using GitLab for continuous integration and deployment workflows face particular risk, as the denial of service can halt automated pipelines and prevent legitimate development activities. The vulnerability also creates opportunities for attackers to perform resource exhaustion attacks that can be combined with other techniques to amplify their impact. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and T1566.002, which involves spearphishing with social engineering techniques that could be used to deliver the malicious GraphQL queries. The vulnerability affects both GitLab Community Edition and Enterprise Edition deployments, making it a widespread concern across the GitLab user base.
Mitigation strategies for this vulnerability should include immediate implementation of query complexity limits and depth restrictions within the GraphQL execution engine. Organizations should configure maximum query depth and complexity thresholds to prevent excessively nested queries from consuming system resources. The recommended approach involves setting appropriate limits on field selection and query nesting levels, typically through GraphQL schema configuration or through GitLab's built-in GraphQL query validation mechanisms. System administrators should also implement monitoring and alerting for unusual CPU consumption patterns and establish automated response procedures for detecting and mitigating such attacks. Regular updates to GitLab installations are crucial, with immediate patching recommended for versions affected by CVE-2025-11042. Additionally, organizations should consider implementing rate limiting at the API level and network-level controls to prevent single users from consuming disproportionate resources. The vulnerability highlights the importance of proper input validation and resource management in GraphQL implementations, serving as a reminder that even well-established API technologies can contain subtle weaknesses that require careful monitoring and protection.