CVE-2026-83535 in OpenStack Platform
Summary
by MITRE • 10/12/2026
A flaw was found in openstack-network-exporter. When an operator configures user authentication but omits or misconfigures Transport Layer Security (TLS), the basic authentication mechanism is silently bypassed. This fail-open design allows an adjacent network attacker to access sensitive Open vSwitch (OVS) and Open Virtual Network (OVN) dataplane metrics without credentials. Consequently, an attacker can enumerate bridge names, port counters, OVN controller state, and host topology, leading to information disclosure.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified in openstack-network-exporter represents a critical security misconfiguration flaw rooted in the application's handling of authentication protocols under specific network conditions. The core issue arises when an operator enables user authentication for the service but fails to properly configure or omit Transport Layer Security (TLS) encryption for the communication channel. In this scenario, the software exhibits a fail-open design pattern where the absence of TLS causes the basic authentication mechanism to be silently bypassed rather than enforced or rejected with an appropriate error message. This behavior indicates that the application logic prioritizes connectivity over security integrity when cryptographic protection is not established, allowing unauthenticated requests to proceed as if they were validly authenticated.
From a technical perspective, this flaw exploits the inherent insecurity of transmitting basic authentication credentials in plaintext over an unencrypted connection. Basic authentication relies on sending username and password pairs encoded in Base64 within HTTP headers, which offers no cryptographic protection against interception or manipulation. When TLS is not enforced, any entity capable of intercepting network traffic can easily decode these credentials if they are sent, but more critically, the vulnerability allows access without even needing to send valid credentials because the authentication check itself is bypassed entirely in the absence of a secure channel. This creates a significant gap where the security boundary defined by user authentication effectively disappears for any attacker positioned on the same network segment or capable of performing man-in-the-middle attacks.
The operational impact of this vulnerability is severe, primarily due to the sensitive nature of the data exposed through Open vSwitch (OVS) and Open Virtual Network (OVN) dataplane metrics. An adjacent network attacker can exploit this flaw to access detailed infrastructure telemetry without providing any credentials. This includes enumerating bridge names, which reveals the logical network topology; accessing port counters that may expose traffic volumes and potential anomalies; viewing OVN controller state information that provides insight into virtual machine connectivity and routing decisions; and mapping host topology details that identify physical servers and their roles within the cloud infrastructure. Such information disclosure significantly aids an attacker in reconnaissance activities, enabling them to map out the environment for subsequent targeted attacks such as lateral movement or denial of service against critical network components.
This vulnerability aligns with CWE-287, which describes Improper Authentication, specifically where authentication is bypassed due to misconfiguration or logic errors. Furthermore, it relates to CWE-319, Cleartext Transmission of Sensitive Information, given the context in which basic auth credentials would be vulnerable if TLS were partially configured but not enforced correctly. In terms of MITRE ATT&CK framework tactics, this flaw facilitates the Reconnaissance phase by allowing an attacker to gather detailed information about the network architecture and virtualization layer without detection or authentication barriers. It also impacts the Discovery tactic as it allows enumeration of specific system resources like bridges and ports that are typically restricted to authorized administrators.
To mitigate this risk, operators must enforce strict TLS configuration for all connections to openstack-network-exporter. This involves ensuring that valid certificates are deployed and that the service is configured to reject any connection attempts that do not utilize HTTPS with strong cipher suites. Additionally, implementing network segmentation policies can limit access to the exporter endpoint only from trusted management networks or specific monitoring systems, thereby reducing the attack surface for adjacent attackers. Regular security audits of configuration files should include checks for TLS enforcement settings and authentication logic consistency to prevent similar fail-open scenarios in other services within the OpenStack ecosystem.