CVE-2026-72680 in Kibana
Summary
by MITRE • 08/13/2026
Kibana Agent Builder A2A JSON-RPC API endpoint derives the identifier of a stored conversation from a user-supplied input, and the ownership check on that identifier does not distinguish between a conversation that does not exist and one that exists but belongs to another user. As a result, an authenticated user holding only the Agent Builder read privilege can supply an identifier already in use by another user in the same space and cause that user's conversation to be replaced and reassigned to the requesting account. The original owner permanently loses access to the conversation and its history. The impact is limited to loss of integrity and availability of the affected conversation; the attacker does not read the overwritten content.
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability exists within the Kibana Agent Builder A2A JSON-RPC API endpoint where the system fails to properly validate user ownership when processing conversation identifiers. The flaw stems from the API's handling of user-supplied inputs that determine which conversation to modify, creating a critical access control weakness that violates fundamental security principles. The system accepts a user-provided identifier without performing adequate validation to ensure the requesting user has legitimate authorization to access or modify that specific conversation resource. This design oversight creates an authentication bypass scenario where an authenticated user with only read privileges can exploit the system's logic error to manipulate conversations belonging to other users within the same administrative space. The vulnerability operates through a simple but effective attack pattern where an attacker supplies a valid conversation identifier that is already associated with another user's account. The system processes this request without proper ownership verification, leading to the automatic replacement and reassignment of the target conversation to the requesting user's account.
The technical implementation of this flaw demonstrates poor input validation and inadequate access control mechanisms that directly contravenes established security standards such as CWE-285 for improper authorization and CWE-346 for origin validation failures. The vulnerability represents a classic case of insecure direct object reference where the system fails to validate that the user has proper authorization to modify the referenced resource. From an operational perspective, this weakness creates a significant integrity and availability impact within the Kibana environment, as it allows malicious actors to permanently disrupt other users' conversation data and potentially destroy valuable historical information. The attack requires minimal privileges but produces severe consequences, making it particularly dangerous in multi-user environments where multiple administrators or analysts may be working within the same space.
The security implications extend beyond simple data loss, as this vulnerability enables a form of privilege escalation through resource manipulation that could be leveraged for further attacks within the compromised environment. While the attacker cannot read the overwritten conversation content, they gain complete control over the conversation's metadata and can effectively erase another user's work, potentially disrupting critical operational workflows or security investigations. The impact is particularly concerning in environments where Agent Builder conversations contain sensitive information about system configurations, security events, or operational activities that other users rely upon for their work. This vulnerability aligns with ATT&CK technique T1078 for valid accounts and T1485 for data manipulation, as it allows unauthorized modification of user data while maintaining the appearance of legitimate system operation.
Mitigation strategies should focus on implementing proper ownership validation checks before any conversation modification operations are permitted. The system must validate that the requesting user has explicit authorization to access or modify the specified conversation identifier, regardless of whether the conversation exists or not. This requires strengthening the access control layer to ensure that all user-supplied identifiers are validated against the current user's permissions and ownership rights. Organizations should also implement comprehensive logging and monitoring of conversation modification activities to detect potential exploitation attempts. Additionally, the system should enforce stricter validation of conversation identifiers to prevent manipulation of resources belonging to other users, including implementing proper error handling that does not reveal whether a conversation exists or belongs to another user. Regular security assessments and input validation reviews should be conducted to identify similar vulnerabilities in other API endpoints within the Kibana ecosystem.