CVE-2021-22217 in Community Edition
Summary
by MITRE • 06/09/2021
A denial of service vulnerability in all versions of GitLab CE/EE before 13.12.2, 13.11.5 or 13.10.5 allows an attacker to cause uncontrolled resource consumption with a specially crafted issue or merge request
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Analysis
by VulDB Data Team • 06/11/2021
The vulnerability identified as CVE-2021-22217 represents a critical denial of service weakness affecting GitLab Community and Enterprise editions across multiple version lines. This flaw exists in all versions prior to 13.12.2, 13.11.5, and 13.10.5, making it a widespread concern for organizations utilizing GitLab as their primary version control and collaboration platform. The vulnerability specifically targets the processing of issue and merge request objects within the GitLab system, creating a scenario where malicious actors can exploit resource consumption patterns to disrupt normal operations.
The technical implementation of this vulnerability stems from insufficient input validation and resource management within GitLab's issue and merge request handling mechanisms. When a specially crafted issue or merge request is submitted to the system, the processing logic fails to properly limit resource consumption during parsing and validation operations. This allows attackers to craft payloads that cause the GitLab instance to consume excessive CPU cycles, memory, or other system resources. The flaw operates at the application layer and can be exploited through the web interface or API endpoints that handle issue and merge request creation or modification operations.
The operational impact of CVE-2021-22217 extends beyond simple service disruption to potentially compromise the entire GitLab infrastructure. Organizations may experience complete unavailability of their GitLab instances, leading to significant productivity losses and potential business continuity issues. The vulnerability can be exploited by attackers with minimal privileges, making it particularly dangerous as it could be leveraged by both external threat actors and insider threats. The resource exhaustion occurs gradually but can quickly overwhelm system resources, potentially causing cascading failures in dependent services or leading to system crashes that require manual intervention and restart procedures.
From a cybersecurity perspective, this vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and represents a classic denial of service attack vector. The flaw can be categorized under the ATT&CK technique T1499.004, "Endpoint Denial of Service," as it targets the GitLab application endpoints to consume system resources. Organizations should immediately implement patch management protocols to upgrade to the affected versions, with the recommended minimum versions being 13.12.2, 13.11.5, or 13.10.5, depending on their current deployment. Additional mitigations include implementing rate limiting on issue and merge request creation operations, monitoring for unusual resource consumption patterns, and configuring automated alerts to detect potential exploitation attempts. Network-level protections such as intrusion detection systems and web application firewalls can provide additional defense in depth measures while the permanent fixes are being deployed across the organization's infrastructure.