Description

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.8, 19.2 before 19.2.6, and 19.3 before 19.3.2 that under certain conditions could allow an authenticated user with Duo Chat access to obtain Advanced Search instance configurations and sensitive credentials using a specially crafted GraphQL subscription argument to bypass serialization and perform server object lookup.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.9",
  "pubDate": "2026-09-12T03:16:31.477Z",
  "pubdate": "2026-09-12T03:16:31.477Z",
  "executiveSummary": "A significant security vulnerability has been identified and remediated in GitLab Enterprise Edition (EE) that could allow unauthorized disclosure of sensitive system configurations and credentials. The vulnerability affects GitLab EE versions ranging from 18.3 prior to 19.1.8, 19.2 prior to 19.2.6, and 19.3 prior to 19.3.2. This security flaw leverages a logic gap in the GraphQL subscription handling mechanism, specifically within the context of the Duo Chat feature.\nTo exploit this vulnerability, an attacker must possess valid authentication credentials on the platform and have authorized access to the Duo Chat interface. Under specific conditions, such a user can submit a specially crafted GraphQL subscription argument. This payload successfully bypasses standard object serialization protocols, triggering an unintended server-side object lookup.\nThe primary risk associated with this vulnerability is the exposure of Advanced Search instance configurations, which frequently contain highly sensitive credentials and infrastructure connection details. Successful exploitation compromises the confidentiality of integration secrets, potentially allowing attackers to gain unauthorized access to external database clusters or perform further lateral movement within the enterprise network environment.",
  "technicalDetails": "The root cause of this vulnerability lies in the improper validation and handling of input arguments within GitLab EE's GraphQL subscription APIs associated with the Duo Chat functionality. GraphQL subscriptions rely on persistent network connections to push real-time updates to clients. During this process, arguments passed to subscription queries must be rigorously serialized and validated to ensure that users can only query or track objects they are explicitly authorized to access.\nBy constructing a subscription request with a specially crafted argument, an authenticated attacker can disrupt the expected serialization pipeline. This failure to properly serialize the input allows the argument to influence the underlying database query or object retrieval logic directly, bypassing the authorization boundaries typically enforced during object mapping.\nOnce the serialization mechanism is bypassed, the application performs an arbitrary server-side object lookup. Instead of resolving the request within the limited context of Duo Chat, the backend resolver processes the input to query database objects associated with the Advanced Search configuration. Advanced Search in GitLab integrates with external indexing engines such as Elasticsearch or OpenSearch, requiring stored administrative credentials, host addresses, and security certificates.\nThe attack flow proceeds systematically: First, the authenticated attacker establishes an active session and accesses the Duo Chat feature interface. Second, the attacker transmits a GraphQL subscription request containing the manipulated argument to the server. Third, the GitLab backend processes the subscription, fails to serialize the argument correctly, and executes an unauthorized database lookup for the Advanced Search configurations. Finally, the application serializes the retrieved configuration object—including sensitive credentials—and returns it directly to the attacker's client session.\nThis vulnerability is restricted to GitLab EE environments where Duo Chat and Advanced Search are configured. It requires network access to the GraphQL endpoint and valid user authentication with permissions to utilize Duo Chat. The post-exploitation impact includes the potential exposure of third-party integration credentials, which could lead to data exfiltration or modification within the connected search cluster."
}