CVE-2026-115364 in OpenBao
Summary
by MITRE • 10/23/2026
OpenBao before 2.6.3 contains a missing authorization check that allows attackers to stop Agent and Proxy services by omitting the X-Vault-Header. When require_request_header is enabled, attackers can send requests via server-side request forgery to /agent/v1/quit or /proxy/v1/quit to shut down these services.
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Analysis
by VulDB Data Team • 10/23/2026
The vulnerability identified in OpenBao versions prior to 2.6.3 represents a critical authorization bypass within the agent and proxy service components, specifically triggered by improper validation of request headers when certain configuration flags are active. The core technical flaw lies in the handling of the X-Vault-Header during administrative operations that terminate services. Under normal operational parameters, OpenBao requires specific authentication tokens or header validations to ensure that only authorized entities can execute privileged commands such as shutting down the agent or proxy processes. However, when the require_request_header configuration option is enabled, a logic error allows an attacker to bypass these checks by omitting the expected X-Vault-Header in their HTTP requests. This omission does not trigger a rejection of the request as intended; instead, it creates a state where the system fails to verify the identity or permissions of the requester before proceeding with sensitive lifecycle management actions.
This flaw is particularly dangerous because it can be exploited through server-side request forgery attacks. In this scenario, an attacker who has compromised a trusted client application or web service that communicates with OpenBao can craft malicious requests directed at the internal endpoints /agent/v1/quit and /proxy/v1/quit. Because these endpoints are often exposed to internal networks for management purposes, they may be accessible from contexts where SSRF is feasible. By leveraging this vector, an attacker can send a request that lacks the X-Vault-Header but still targets the quit endpoint. The server interprets this malformed or header-less request as valid due to the missing authorization check, leading to the immediate termination of the OpenBao agent and proxy services. This bypass effectively neutralizes the security controls designed to protect these administrative interfaces from unauthorized access.
The operational impact of this vulnerability is severe, primarily characterized by a denial of service against critical infrastructure components. The ability for an attacker to remotely shut down Agent and Proxy services disrupts the availability of OpenBao’s core functionalities, including secret management, encryption as a service, and dynamic credential generation. For organizations relying on OpenBao for securing their applications and data pipelines, this outage can lead to significant business disruption, preventing authorized users from accessing secrets or performing cryptographic operations. Furthermore, in high-availability clusters, the unexpected termination of these services could trigger failover mechanisms that may themselves introduce instability or further degrade system performance during recovery. The lack of proper authorization ensures that even low-privileged attackers with network access can cause substantial downtime without needing valid credentials for other administrative functions.
From a classification perspective, this vulnerability aligns with CWE-287, which describes Improper Authentication, as the system fails to adequately verify the identity of the user before granting access to sensitive operations. It also relates closely to CWE-639, Authorization Bypass Through User-Controlled Key, since the absence or manipulation of a specific header acts as an uncontrolled key that bypasses security measures. In terms of offensive tactics, this exploit maps to MITRE ATT&CK technique T1071, Application Layer Protocol, specifically within the context of web protocols where attackers abuse legitimate communication channels for malicious purposes. It also reflects aspects of T1499, Endpoint Denial of Service, as the ultimate goal and result are the disruption of service availability on the targeted endpoints.
To mitigate this vulnerability, organizations running OpenBao versions earlier than 2.6.3 must upgrade to version 2.6.3 or later immediately upon release. This update addresses the logic error in the header validation process for agent and proxy quit commands. In addition to upgrading, administrators should review their network segmentation strategies to ensure that internal management endpoints like /agent/v1/quit are not exposed to untrusted networks or potentially compromised client applications susceptible to SSRF attacks. Implementing strict firewall rules or API gateways that validate request origins can provide an additional layer of defense. Furthermore, enabling comprehensive logging and monitoring for these specific endpoints will aid in detecting any attempted exploitation attempts before they result in service disruption. Regular security audits focusing on authorization checks for administrative APIs are recommended to prevent similar bypasses in other components of the OpenBao ecosystem.