Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.2 before 18.11.11, 19.0 before 19.0.8, 19.1 before 19.1.6, and 19.2 before 19.2.4 that under certain conditions could allow an unauthenticated user to remotely modify or delete public projects and user data via a GraphQL directive.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.4",
  "pubDate": "2026-08-17T20:16:41.777Z",
  "pubdate": "2026-08-17T20:16:41.777Z",
  "executiveSummary": "An unauthorized data modification vulnerability has been identified in GitLab CE/EE affecting multiple version branches. Specifically, the flaw impacts all versions from 18.2 before 18.11.11, 19.0 before 19.0.8, 19.1 before 19.1.6, and 19.2 before 19.2.4. Under certain conditions, this security defect permits an unauthenticated remote attacker to interact with and modify or delete public projects and user data. The root cause lies in how the application processes specific GraphQL directives, bypassing standard access control mechanisms. The risk implications are severe, as unauthorized data tampering and destruction of public projects undermine the integrity and availability of the affected GitLab deployments. Exploitation requires network access to the target GitLab instance and the ability to craft malicious GraphQL queries containing the vulnerable directive. No prior authentication or elevated privileges are required by the threat actor, making external exposure a critical concern for organizations running vulnerable versions.",
  "technicalDetails": "The vulnerability resides within the GraphQL API component of GitLab CE/EE, which handles client queries and mutations through a unified interface. The root cause stems from insufficient authorization checks and improper validation of input when specific GraphQL directives are supplied within incoming requests. Typically, GraphQL schemas enforce strict authentication and authorization layers at the resolver or field level to ensure that unauthenticated users cannot execute mutating operations such as updates or deletions. However, under the specific conditions governed by this vulnerability, the parsing and execution engine fails to properly evaluate the identity and permissions of the caller when processing the malicious directive.\nThe attack flow begins when an unauthenticated remote attacker crafts an HTTP request directed at the GitLab GraphQL endpoint. Instead of using standard mutation verbs that would typically trigger immediate authentication failures, the attacker embeds the targeted GraphQL directive within the query payload. Upon receiving the request, the vulnerable GraphQL component processes the directive without adequately verifying session tokens or API credentials. Because the authorization context is improperly established or bypassed during the resolution phase, the underlying controllers process the command as if it originated from an authorized user or system process.\nThis behavior allows the payload to reach internal application logic responsible for project and user data management. Consequently, the attacker can successfully issue commands to modify or delete public projects and sensitive user data across the instance. The network exposure is broad, as the GraphQL endpoint is publicly accessible in standard GitLab deployments. The exploitation prerequisites are minimal, requiring only network reachability to the target server and a crafted payload leveraging the flawed directive. Post-exploitation impact includes unauthorized data loss, defacement or destruction of public repositories, and compromise of user data integrity."
}