CVE-2026-2845 in Community Edition
Summary
by MITRE • 02/26/2026
An issue has been discovered in GitLab CE/EE affecting all versions from 11.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1 that could have allowed an authenticated user to cause denial of service by exploiting a Bitbucket Server import endpoint via repeatedly sending large responses.
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Analysis
by VulDB Data Team • 03/01/2026
This vulnerability exists within GitLab Community Edition and Enterprise Edition products across multiple version ranges, specifically impacting installations from version 11.2 through 18.7.4, 18.8 through 18.8.4, and 18.9 through 18.9.0. The flaw resides in the Bitbucket Server import endpoint functionality that handles data transfer operations between GitLab and Bitbucket Server instances. The vulnerability stems from inadequate input validation and resource management within the import process, allowing malicious actors to exploit the system through carefully crafted requests that generate excessively large responses. This represents a classic denial of service condition where legitimate system resources become consumed through repeated exploitation attempts, ultimately rendering the affected service unavailable to authorized users.
The technical exploitation occurs when an authenticated user leverages the Bitbucket Server import endpoint to initiate data synchronization processes that are designed to handle standard data volumes. However, the system fails to properly validate the size or complexity of responses generated during these import operations, creating a resource exhaustion scenario. Attackers can repeatedly send requests that trigger the generation of oversized response payloads, causing memory allocation failures, process timeouts, or system resource exhaustion that effectively disables the import functionality. This vulnerability aligns with CWE-400 which catalogs weaknesses related to resource exhaustion and improper input validation. The attack vector specifically targets the import endpoint through authenticated sessions, making it particularly dangerous in environments where multiple users have access to GitLab systems.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire GitLab platform availability. When exploited successfully, the denial of service condition can affect not only the specific import functionality but also potentially impact other concurrent operations that share system resources. The vulnerability affects organizations that rely on GitLab for version control and collaboration, where the import functionality from Bitbucket Server is commonly used for migration purposes or integration with existing infrastructure. Organizations using GitLab in production environments may face significant operational disruptions, including loss of access to version control features, delayed development workflows, and potential impact on continuous integration and deployment pipelines that depend on GitLab's core functionality.
Organizations should immediately implement mitigation strategies including upgrading to the patched versions mentioned in the advisory, which address the resource management issues within the Bitbucket Server import endpoint. Network-level protections such as rate limiting and request size restrictions can help minimize the impact of potential exploitation attempts, though these measures are considered temporary safeguards rather than permanent solutions. System administrators should monitor for unusual import activity patterns that might indicate exploitation attempts, and implement proper access controls to limit the number of users who can initiate Bitbucket Server imports. The vulnerability demonstrates the importance of proper input validation and resource management in web applications, aligning with ATT&CK technique T1499 which covers resource exhaustion attacks. Organizations should also consider implementing automated monitoring and alerting systems that can detect anomalous behavior patterns consistent with denial of service exploitation attempts.